BULGARIAN ACADEMY OF SCIENCES

 

CENTRAL LABORATORY
OF MINERALOGY AND CRYSTALLOGRAPHY

ANNUAL REPORT
No 11/2005

 

Editor: Dr. Nikola Zidarov; E-mail: nzidarov@interbgc.com
© Central Laboratory of Mineralogy and Crystallography, 2006
ISSN 3033-2206

CONTENTS


Projects NoNo 1.4, 17, 20, 22, 25, 26 are financially supported in part by the Bulgarian National Science Fund of the Ministry of Education and Science. Projects NoNo 2 and 10 are financially supported in part by the Swiss National Science Foundation.

INTRODUCTION

This annual report presents the activities of the Central Laboratory of Mineralogy and Crystallography during the eleventh year of its existence.
The topics developed were in accordance with the politics and progams for realization of the strategy, aims, and priorities of BAS in the period up to 2007.

1. The most important scientific results may be grouped as follows:

2. The most important scientific and practical achievements are:

3. The most important results obtained in the framework of the international collaboration of CLMC are:

Scientific activity

During the year the activity was concentrated in 8 projects financed by the budget of the Bulgarian Academy of Sciences, 3 projects additionally financially supported by the National Council for Scientific Investigation, 4 projects in the framework of the international collaboration, and 2 contracts with organizations in Bulgaria and from abroad. The scientific results achieved by the stuff of CLMC in 2005 were reported in 115 publications in scientific journals and series, 43 of which in international and foreign journals and proceedings, and 70 in Bulgarian issues. The already published papers are 107 in number, whereas those in press are 8. Our colleagues have given 66 reports in international and local conferences and symposiums, with 19 of them being presented on international scientific events or such with an international participation.
Of a national character is the fulfillment of the program ”Design and structural analysis of nano-sized regions in functional materials” in the framework of the national program “Nano-technologies and nano-materials”. Since the end of 2005, CLMC is taking part, together with Asarel-Medet Ltd and NIPRORUDA Ltd, in the scientific project “Development of technology for combined extraction of gold from copper ore”, which is partially financed by the National Agency for Encouraging small and Medium enterprises.
Users of our scientific products are a number of leading industrial companies like Kaolin AD, Solvei-Sodi Ad, Sofarma AD, Titan AD, Biovet AD, Terrachim AD, Tehcem AD, Chelopech mining AD, Zlatna Panega Cement AD, as well as 8 scientific institutes of BAS, Sofia University, Academy of Medicine, etc.

Most important events for CLMC during 2005 were:

During the year, S. Vassilev was graduated with a DSc degree and Dr. B. Mihailova lectured as a visitor professor at the Faculty of Earth Sciences, University of Hamburg, Germany on “Spectroscopy of minerals” and “Crystal Physics”.  A course in “Applied mineralogy” for M.Sc degree was carried out for the purposes of the University of Mining and Geology “St. Ivan Rilski”, Sofia.

 

Nikola Zidarov
Sofia, January, 2006

RESEARCH TOPICS:

I. MINERAL SYSTEMS AND ISOTOPE GEOCHEMISTRY

1. Mineral-petrologycal, geochemical and isotope studies of geological units in Serbo-Macedonian Massif, SW Bulgaria

1.1. Skrut granitoids (N. Zidarov, I. Peytcheva, A. v. Quadt, E. Tarassova, R. Titorenkova, V. Andreichev)

The Skrut granitoids crop out over an area of about 13 km2 in Belassitsa Mountain, SW Bulgaria, south of the village Skrut and near to the border with the Republic of Macedonia. They belong to the Ograzhden Block of the Serbo-Macedonian Massif (SMM). New mineralogical, petrological and geochemical studies of the Skrut granitoids are summarized by Zidarov et al. [69, 118]. Rb-Sr whole rock isotope data suppose Jurassic time of magma generation (Zidarov et al., Ann. Rep. 8, 2002). The present study focuses on the isotope and geochemical features of the zircons with the aim to specify aging, using U-Pb isotope single grain method and ID-TIMS (Isotope Dilution Thermal Ionisation Mass Spectrometry) technique. Zircon morphology, e-Hf characteristics and REE-distribution of the zircons are used to unravel the geochemical evolution of the magma [69]. Zircon saturation thermometry contributes to constrain the temperature of magma generation.

The zircons from the Skrut granitoids reveal dominant growth of the prism {110} and the bipyramid {101}. CL-images of the zircons show oscillatory magmatic zoning without dissolution surfaces and give evidence for high Zr-saturation of the melt. The prevailing morphological types, defined according to the typology method of Pupin (1980), are S4, S5, S8, P1, P3, G1. The typological evolution develops from the subtypes S14-15 trough S4-5 and ends with G1. The zircon populations are characterized by relatively low I.T temperature indexes (340-360) and higher values of the index I.A (550-600). These features, as also the growth of the bipyramid {101}, suppose high alkalinity of the magma. The typological evolution trend of the zircons of Skrut granitoids overlaps with the calc-alkaline magmatic trend of Pupin (1980).

High-precision U-Pb single grain method and ID-TIMS technique are used for the dating of zircons from sample 115. Long prismatic beige grains with prevailing bipyramidal {101} and prismatic {110} faces are chosen for the analyses. Two of the measured zircons are additionally abraded to avoid radiogenic lead loss from the rims, which are usually richer in uranium. For the calculation of the age the program ISOPLOT is used. All corresponding points are concordant and yield a concordia age of 248.85 ± 0.70 Ma (Fig. 1). The e-Hf values of the measured zircons range from +1.6 to +3.9 and argue for mixed crust-mantle source of the magma.

Chondrite normalized REE patterns of zircons from samples 144 and 115 are similar and typical for igneous rocks. They are characterized by decreasing LREE and steep encreasing of HREE. The positive Ce-anomalies give evidence for positive oxidation state of the magma and the negative Eu-anomaly is best explained with the fractionation of the plagioclase.

Zircon saturation thermometry is calculated using the equation of Watson and Harrison (1983), which rearranged for T yields a geothermometer for melt:

Fig. 1 Concordia diagram for zircons
from sample B-115, Scrut granite.

Tzr = 12900/[2.95 + 0.85M + ln(496000/Zrmelt)]

In this equation Tzr is the zircon saturation temperature in Kelvins (however, all temperatures in the following text have been converted to C), M is the (Na + K +2*Ca)/(Al*Si) ratio, all in cation fraction, Zrmelt is the concentration of Zr in the saturated melt (measured in the rock sample) in ppm, and 496000 is the concentration of Zr (ppm) in zircon.

The calculated zircon saturation temperatures of the Skrut granitoids range from 780 to 810°C, lying in the marginal field of the "cold" (T< 800°C) and "hot" (T> 800°C) granites.

The U-Pb high-precision zircon age of the Skrut granitoids (248.85 ± 0.70 Ma) is comparable with recently published data of the Igralishte granite (240 + 13/-9 Ma) (Zidarov et al., 2004, Ann. Rep. 10, 2004). In the Greek part of SMM a possible candidate for correlation may be the "variably overprinted" Arnea granite, as its zircons yield ages from 210 to 230 Ma (single zircon evaporation method, Himmerkus et al., 2003). Noteworthy is the fact that whole rock samples from both the Skrut and Arnea granitoids define "isochrones?" with an age of 167.3 ± 8.1 Ma (Zidarov et al., Ann. Rep. 8, 2002) and 155 ± 11 Ma, respectively. It is still not clear if these numbers reflect a real geological process related to the evolution of the western situated Vardar zone or are meanless errorchrones. The latter could result from mixing of two different primary magmas or from high-temperature overprint (metamorphism?). Missing isotope data on timing of the overprinting processes in Belassitsa Mountain hamper our proper interpretation so far.

Lower Triassic ages of granite magmatism in the SMM are new in the geological literature. In the adjacent Rhodope Massif I-type metagranites with a similar age overprinted by the Late Alpine metamorphism crop out in the Central Rhodopes. Upper Permian/Lower Triassic basic magmatism was recently also found in the Rhodopes. All these facts suggest two possible scenarios to explain the formation of the Skrut granitoids and the almost contemporary felsic and basic magmatism: one is post-collisional collapse, thinning of the crust, allowing the intrusion of basic magmas, melting of the crust, as well as different mixing processes between the contrasting magmas; the second supposes rifting or at least on-setting of deep (trans)tensional faults allowing intrusion of mantle and/or lower crustal magmas, and again melting of different parts of the crust and mixing.

Further studies will contribute to constrain the geodynamic reconstructions of the region from the formation of the magmas to their geodynamic and metamorphic evolution.

1.2. Kyanite-staurolite-garnet orthoschists (L. Macheva, R. Titorenkova, N. Zidarov)

The metamorphic basement of Ograzhden Mountain, SW Bulgaria, is built up mainly of Ordovician metagranitoids (equigranular and porphyritic), overprinted by upper amphibolite facies metamorphism, heterogeneous deformation and migmatisation. In the vicinity of the village Lebnitza a thin body of kyanite-staurolite-garnet schists, previously described as metapelites, can be mapped at the contact between the two metagranitoid varieties (Fig. 1). Our investigations revealed some peculiarities leading to interpretation of these rocks as orthoschists, formed in a high temperature deep crustal shear zone [41].

The studied schist body, with a thickness from 10 to 50 m can be traced several kilometers along the strike. It reveals a distinct zonality (Fig. 1, top-right insertion) with variations from rocks highly resembling metagranites to high aluminous schists: Zone 1 - strongly foliated mica-rich metagranites bearing scarce kyanite streaks; Zone 2 - highly mylonitized melanocratic tourmaline-garnet two-mica schists; Zone 3 - coarse-grained schists, built up of large garnet poikiloblasts and elongated kyanite segregations both set up in a quartz-mica matrix, and Zone 4 (the central part of the body) - highly differentiated rocks, built up of alternating kyanite- and quartz-enriched layers 10-15 cm in thickness. Pale-blue to white colored thin layers of kyanite mylonite can be seen in the last zone.

Fig. 1. Geological sketch map of the eastern slopes of the Ograzhden Mountain.
1 – Quaternary; 2 Tertiary volcanic rocks; 3a Equigranular metagranites;
3b Porphyritic metagranites; 4 Kyanite-staurolite-garnet-bearing schists;
5 Amphibolites. Inserted figure (top right) - schematic picture
of the zonal schist body across the profile line.

The texture and the mineral composition of gneisses in zone 1 strongly resemble that of metagranitoids (Pl + Bt + Mu + Kfs+ Qtz + Ru + Ilm + Ap + Zr). Additionally, small kyanite and garnet grains are present, formed on the account respectively of plagioclase and biotite. The mineralogy of zone 2 is presented by large biotite and white mica flakes, minor amounts of plagioclase and quartz. Two garnet generations (coarse-grained, synkinematic poikiloblasts with inclusions of white mica, kyanite and quartz and small-grained (0.1-0.3 mm) late kinematic garnet) are scattered in all other minerals. Zone 3 is a typical aluminous schist, containing two garnet generations and large kyanite segregations with nodular appearance set up in a quartz-mica matrix. Kyanite nodules, made up of small bent radial-arranged crystals, are with clearly pseudomorphic character. Scarce staurolite porphyroblasts are formed after kyanite nodules. Quartz-rich layers in zone 4 are built up of 90-95% quartz plus a minor amount of finely grained white mica, biotite, and small garnet crystals. The kyanite layers are intensively sericitized and mica rich. Prismatic staurolite and chloritoid porphyroblasts without any preffered orientation grow at the expense of kyanite nodules, obviously in a static manner.

Thin kyanite needles, which are parallel to the foliation, wrap the sericitised nodules. In highly mylonitized kyanite mylonites one observes stripes of finely grained garnet and such of kyanite needles, alternating parallel to the foliation.

Garnet is almandine rich (Alm76-86Pyr7-16Grs1-7 Sps2-7) with plateau-like profiles for FeO, CaO and MnO, which is typical of high-grade metamorphism. The coexisting small-grained garnet is chemically homogeneous and of the same composition as the rims of the large-sized garnet. Staurolite and chloritoid are unzoned with XFe 0.77-0.82 and 0.84-0.88, respectively. Chloritoid is more magnesian than both staurolite and garnet, which is typical of the retrograde formation. Two generations of white mica are distinguished on textural grounds: 1) an early kinematic one, with a relatively high celadonite content (up to 3.34 p.f.u.) and a low paragonite component (to 0.12 p.f.u.); 2) syn- to late kinematic, characterized with a moderate to low Si content (3.08-3.18 p.f.u.) and a relatively low paragonite component (0.13-0.22). We suppose early-kinematic white micas to be formed at high temperatures and the second generation – at lower temperatures. The biotite composition is quite uniform with high XFe (0.50-0.62) and Al contents of 0.40-0.51 p.f.u.

On the basis of structural and chemical observations the following sequence of mineral growth can be outlined: garnet + kyanite + quartz + white micaI + biotite? + tourmaline ® sericite ® staurolite + chloritoid + quartz + white micaII.

The calculated pressure and temperature conditions are: T ~ 670oC and pmin = 7 kbar for the peak of the metamorphism and Tmax = 550oC for the retrograde staurolite and chloritoid formation. The time of the kyanite retrogression to sericite remains, however, unknown.

The whole rock chemical composition display significant deviation from the real pelite compositions toward AF-side of the AFM-diagram (Fig. 2).

The zircon morphology from the schists studied resembles strongly that of zircon from metagranitoids, although crystals with curved and resorbed surfaces dominate.These peculiarities could be explained with a higher degree of migmatisation and fluid activity in the shear zone. The obtained SEM images give evidence for secondary alteration processes.

Fig. 2. AFM-diagram. Circles metapelite composition,
Squares metagranite composition. The fields of high-
and low-Al pelites after Spear (1993).

Based on complex field, petrological, geochemical and zircon typology investigations, an orthometamorphic origin of the schists, cropping out in the vicinity of Lebnitza village as well as in other localities of Belasitza and Ograzhden Mountains, is suggested. The distinct zonation of the schist body indicates a dramatic change in the mineralogical composition from granite at the wall rocks to garnet-kyanite schists with staurolite and chloritoid in the zone center. The chemical composition of the rocks shows also substantial change - mass-balance calculations display vast component redistribution between different zones. All processes of such transformations are possible in the presence of canalized fluid flow through a deep crustal shear zone.

1.3. Accessory zircon from melanocratic microgranular enclaves in metagranites (R. Titorenkova, L. Macheva)

The main part of the eastern slopes of the Ograzhden Mountain is built up of metagranitoids with Ordovician age. Mafic sheets and enclaves of varying sizes and shapes and granodiorite to quartz diorite composition are commonly hosted by granites (Ann. Rep. 7/2001, 8/2002, 9/2003). The presence of such enclaves in metagranites is one of the evidences for their ortho-origin. Melanocratic microgranular enclaves are fine-grained with microlepidogranoblastic texture, composed of plagioclase, quartz, biotite, apatite, and zircon. Zircon is the only preserved relict mineral and this is the reason for the detailed study of its morphology, internal textures and chemical composition using cathodoluminescence, backscattered images and electron microprobe analyses [80].

The external morphology was determined by the typological method. The zircon morphotypes in melanocratic enclaves vary from L4-5, S4, S5, S3 (which are typical of hosted metagranites) (Fig.1a) to S20-24 and J (Fig.1b). The mean point of the population is at I. = 376 and I. = 442. The temperature index I. points to crystallization temperatures from 900 to 600oC and the chemical index I. to a more alkaline rock-source as compared to metagranites.

Fig. 1. External form of zircon from melanocratic enclaves in metagranites: a) short prismatic crystal, morphological type S20-25; b) crystal with predominantly developed bipyramid {211} typical for Al-metagranites. Marker 100 mm.

The CL and BSE images show a broad range of internal textures. According to these images some crystals do not contain inherited cores, whereas other have large-sized, sometimes idiomorphic cores. Overgrowths of different thickness are observed, which can be interpreted either as metamorphic or as magmatic growth. When this overgrowth is substantially thick with traces of zonality and high content of impurities, we consider that it reflects the crystal growth during the interaction with per- Al granitic melt. On the other hand, when the rim is thin, poor in impurities, bright in CL images and without growing textures, we consider as more probable explanation its being a result of metamorphic alteration of the primary crystal.

Fig. 2. a) BSE image of zircon crystal from metagranites, morphological type S20-25, containing large core and zonal overgrowth; b) The ratio ZrO2/HfO2 across profile A-B-C; c) The distribution of hafnium and yttrium for the core (1) and for the zonal overgrowth (2) plotted on the Y2O3/HfO2 diagram.

Figure 2a presents a zircon crystal from less deformed metagranites (M-27) with an external form (S25) typical of melanocratic enclaves, which contains a large {100}-prism-core governing the final {100}-morphology of zircon in granitic melt.

The chemical composition of zircon core is characterized with a lower content of U, Y, P and Hf than that of the overgrowth (Fig. 2b). Zircon from melanocratic enclaves reveals HfO2 content in the range from 0,11 wt% to 1.5 wt% and content of Y2O3 from 0 to 0.2 wt%. On the basis of the ZrO2/HfO2 ratio being above 45, and the diagram HfO2/Y2O3 we may define a basic-to-intermediate Ca-alkaline rock-source for the core and a granitic source for the overgrowth (Fig. 2c).

The obtained results on the morphology, internal textures and chemical composition of zircon from melanocratic enclaves point to the following conclusion: the presence of idiomorphic zircon crystals with morphology and chemical composition typical of basic- to-intermediate magmatic rocks, as well as the presence of such crystals in metagranites indicate a possible granite intrusion upon active interaction with basic magma, e.i. magma-mixing processes.

1.4. Occurrence, chemical composition and electron-probe dating of accessory REE-Y-Th-U minerals from Igralishte granite pluton (M. Tarassov, E. Tarassova)

The Igralishte pluton is mainly composed of muscovite-biotite granite and rarely of leucocratic muscovite granite. The geochemical (ASI = 1.04-1.31) and isotopic (87Sr/86Sr = 0.70804) characteristics of the intrusive define its rocks as peraluminous S-type granites crystallized from high-potassium calc-alkaline magma. The pluton age is accepted to be of about 240 Ma (Ann. Report 10/2004). Monazite, xenotime, and their alteration products (allanite, thorite/huttonite, uraninite) are found to be major carriers of REE, Y, Th, and U in the granite constituting about 0.3% of the rock volume. Recently, we employed the electron-probe method for the age dating of monazite from Igralishte granite pluton and attained very good correspondence with the isotopic age. This result encouraged us to further apply the method for other Th-U containing accessory minerals from the pluton. For this purpose, several samples of biotite-muscovite and muscovite granites of the pluton were selected, and occurrence, chemical composition, relationships, and secondary alterations of REE-Y-Th-U minerals in them were studied [76, 77]. Two types of Ce-monazite with zoned microstructure, close chemical composition and similar assemblages of secondary minerals, but with different age being ~ 240 and ~ 300 Ma, respectively, were found (Fig. 1). Xenotime is presented by two varieties: magmatic one (Fig. 2), encountered in muscovite-biotite granite only, and postmagmatic one, found in both types of granite. The chondrite normalized REE patterns of the two types of xenotime differ significantly, especially in the region of Tb, Dy and Ho, which demonstrates much greater enrichment in the postmagmatic xenotime. Electron-probe dating of the magmatic xenotime yields ages between 230 and 260 Ma, well corresponding to the ages of the younger monazite (240 Ma). Allanite is a typical postmagmatic REE mineral in the pluton and together with apatite it replaces monazite. Thorite and uraninite are secondary minerals replacing monazite and xenotime, respectively. The electron-probe dating of both actinide minerals gave rather obscure results. For example, thorite ages obtained vary in the range 130-180 Ma thus indicating much younger ages for the postmagamtic processes in the Igralishte pluton. Uraninite ages (180-220 Ma) are more acceptable, because they partially correspond to the younger monazite ages. The obtained data on the accessory minerals (their microstructure, relationships with other rock-forming minerals) as well as the electron- probe dating allow one to accept the age of ~240 Ma as corresponding to formation of monazite and xenotime in magmatic melt. The formation of secondary allanite, xenotime, thorite/huttonite and uraninite is related to high-temperature alkaline autometasomatic alteration of the granite. The possible reasons for the younger ages obtained by electron-probe dating for the secondary Th-U minerals, especially those for thorite, are either these minerals have been undergone additional metasomatic alteration or there are some problems in the applied method that needs further elaboration. The older monazite (~300 Ma) revealed during the present investigation seems to be relic form whose well preserved zoned structure evidences that the melted Paleozoic protolite have been of magmatic origin.

Fig. 1. Zonal microstructure of monazite. Grain from the heavy fraction. SEM, BSE image.

Fig. 2. Xenotime relic crystal replaced by pseudomorphic apatite + uraninite.
Grain from the heavy fraction. SEM, BSE image.

2. Isotope-geochemical and geochronological investigation of magmatism and related ore formation in Srednogorie zone (I. Peytcheva, A. v. Quadt, B. Kamenov, D. Stoyanov)

The ApuseniBanatTimokSrednogorie (ABTS) belt, Europe's most extensive belt of calc-alkaline magmatism and Cu-Au mineralisation, is related to the subduction of the Tethys ocean beneath the European continental margin during the Late Cretaceous phase of the AlpineHimalayan orogeny. Extensive U-Pb dating of zircons from subvolcanic intrusions and major plutons in Central Srednogorie in the last 5 years revealed a general youngling of the magmatism from ~92 Ma in the north (Elatsite) to ~78 Ma in the south (Kapitan Dimitrievo). The magmatism and ore formation in individual magmatic-hydrothermal complexes along the profile has lived much shorter-less than 1 m.y. The age progression correlates with a north-to-south geochemical trend of decreasing crustal input into mantle-derived magmas [68, 97, 141] and is explained as a consequence of slab retreat during oblique subduction [2]. Noteworthy Cu-Au deposits are restricted to the northern and central part of the profile (ranging in age from ~ 92 to ~ 86 Ma), while the southernmost part exposes more deeply eroded mid-crustal plutons devoid of economic mineralization [68, 97]. Accretion of continental fragments south of the ABTS belt - in the Rhodopes is suggested to explain this phenomenon, which led to greater uplift of the youngest Late Cretaceous intrusions and removed any ore deposits that might have been formed in this area [97].

More to the south, in the Rhodopes, the Alpine magmatism is dated mainly as post-Palaeocene in age, but an Upper Cretaceous one is also supposed by many authors. In the Rila-West Rhodopes batholith an Upper Cretaceous pre-metamorphic unit of plastically deformed hornblend-biotite granitoids (» 80 Ma) was distinguished. The batholith is situated directly south of the western parts of Central Srednogorie and provides good opportunity to follow the evolution of the magmatism to the accreted continental fragments. Present study focuses on the isotope-geochronological and geochemical features of the presumably Upper Cretaceous rocks in Eastern Rila and Western Rhodopes. Conventional U-Pb isotope single grain zircon method and ID-TIMS (Isotope Dilution Thermal Ionisation Mass Spectrometry) technique are used to specify aging. Sr and Nd whole-rock, as well as Hf-zircon isotope studies contribute to constrain the magma sources.

The granitoids of the Rila-West Rhodopes batholith crop out over more then 2000 km2 in the Rila and the Rhodope Mountains. They consist of three main rock types: hornblend-biotite and biotite granodiorites (unit 1), biotite and two mica granites (unit 2) and fine-grained leucogranites and aplitoid granites (unit 3). The granitoids from the first unit, which are the main topic of this study, are coarse grained, melanocratic, inequigranular to porphyritic. In all outcrops they are variably overprinted and plastically deformed. The metamorphic foliation is low grade (10-25°) dipping to the NNW-NNE. It is entirely conform to the foliation of the country metamorphic rocks. The syn-kinematic shear criteria show top-to-SSE-SSW direction of the synmetamorphic transport.

The samples for the present study are from the Belmeken and Gruntcharitsa bodies of the first granodiorite unit (AvQ159 and V3P). Most analyzed zircons are concordant or almost concordant (Fig. 1). The grains with the best fit of the 206Pb/238U and 207Pb/235U ages are used to calculate concordia ages of 69.26 ± 0.26 Ma and 66.79 ± 0.29 Ma, respectively. Consequently, the Upper Cretaceous magmatism proceeded between 66.5 and 69.5 Ma (the error uncertainties included).

The calculated zircon saturation temperatures of the Rila-West Rhodopes granitoids lie in the field of the "cold" (T< 800°C) granites, generated in the crust. However, the zircon saturation temperature of the Upper Cretaceous first unit granitoids range from 755 to 783°C (average of 770oC) and is about 30°C higher than these of the granites from the main phase of unit two (average of 740°C).

The Nd and Sr isotope characteristics give evidence for mixed and not homogenized sources of the granitoid magma, but emphasize the differences between units 1 and 2. The granodiorites of unit 1 reveal crust-mantle features with e-Nd (70) in the range from -3.3 to +0.6 and initial (87Sr/86Sr) of 0.7064-0.7066. The granites of unit 2 are crust dominated, showing e-Nd (40) from -2.6 to -9.1 and (87Sr/86Sr) of 0.7065-0.7085. These conclusions are confirmed by the e-Hf values of the zircons, ranging from +1.4 to +5.1 in the granodiorites of unit 1 and around 0 (-0.8 to +1.9) in the granites of unit 2.

Fig. 1. Concordia diagram for zircons of samples
AvQ159 and V3P (filled symbols).

The new precise single crystal U-Pb zircon data confirm the age differences of the Rila-West Rhodopes granitoids of unit 1, from one side, and unit 2 and 3, from the other. The plastically deformed granodiorites of unit 1 reveal crust-mantle isotope characteristics and geochemical similarities to the Srednogorie type magmatism. Furthermore, the magmatism gets not only younger to the south, but also more crustal influenced [96], which give evidence for real change in the geodynamic environment in Maastrichtian time after the accretion of continental fragments south of the ABTS belt. Why do the granitoids with different age crop now together in "one batholith"? So far we can just suppose a Late Alpine exhumation of both granitoids, connected with the postcollisional collapse of the stacked crust in the Rhodope region. The mechanism of the metamorphic core complex could be a possible explanation, but this idea remains just a hypothesis without detailed structural data.

The Apuseni–Banat–Timok–Srednogorie (ABTS) and the Central Srednogorie of Bulgaria provide good opportunities for studying magma mixing/mingling processes and it is well known that world class Cu-Au porphyry and epithermal type ore deposits are linked to mixed magmatic suites. The mixing can lead to magmatic volatile saturation, which can potentially trigger volcanic eruptions and/or the formation of magmatic-hydrothermal ore deposits. In the frame of GEODE-project of the ESF extensive isotope-geochronological and geochemical studies are made to understand the duration and mechanism of magma mixing. The fast crystallisation of U- and REE-rich zircons in hybrid gabbros of the southern plutons of Central Srednogorie are explained with mixing of the mantle magma (additional to the mingling) with crustal melt and magma degassing at mid- to upper crustal levels [137].

3. Comparative characteristics of carbonate-hosted sedimentary exhalative polymetallic deposits (Z. Damyanov)

Based on the analysis of the descriptive (quantitative and qualitative) geological, mineralogical and geochemical data available so far (from references and our studies), a comparative characterization of the polymetallic (+ spatially related barite) deposits from the West Balkan (Kremikovtsi-Vratsa ore district) has been carried out. The great part of these deposits are hosted in sedimentary rocks but the explored reserves are located mainly in Triassic carbonate rocks. The deposits from the region are characterized by: different morphology of ore bodies (stratiform, stratabound, veins), various host rock lithology (carbonates, sandstones, shales, basement metamorphites), different geotectonic settings (embrional rifting, passive margin, interrift horst-shaped and compressional zones), specific ore-hosting structures (local second-order synsedimentary basinal depressions and activated basement faults, non-tectonic depressions near third-order faults, associated with regional lineaments, compressional cutting-fissures zones), typical (as a rule) ore and geochemical zoning, generally low temperature of formation (<200oC), and variable ore composition (Fe±Mn, Zn, Pb, Cu, Ba, Ag, Hg).

The comparison and analysis of the available data allow to reveal the genetically most important and incontestable mineralogical, geochemical and geological facts, the interpretation of which does not contradict to all the rest basic characteristics and logically enter into the proposed attempt to summary interpretation of the origin of the deposits from the region. Based on that, a geological-genetic model of ore formation of the polymetallic carbonate-hosted deposits from the West Balkan (Kremikovtsi-Vratsa ore district) as a result of polystage and polygenic Triassic metallogenesis is proposed. Later tectonomagmatic events have left their imprints on the primary ores and provoked new mineralization (but low ore-forming) processes that has led to transformation and modification of the primary ore bodies. The proposed model for relatively synchronous to the host carbonate rocks polymetallic ore formation insists on adopting of new strategy of prospecting and exploration in the region, based mainly on lithologic-stratigraphic and geochemical criteria and methods but not so much on tectonic-structural ones used so far.

4. Platinum-group minerals from sediments of Straldzha graben, Eastern Srednogorie (Z. Tsintsov)

Individual grains of platinum-group minerals (PGM) isolated from alluvial sediments of central and western parts of Straldzha graben (Eastern Srednogorie) are investigated [81]. This is a new occurrence of such type of mineralization in Bulgaria. The concentration of PGM is very low and below 1 mg/m3. Only alloys of Pt-Fe and Os-Ir-Ru are presented in ratio about 20:1, all in grain fractions (classes) <100 mm. Inclusions of silica glass and Os-Ir-Ru alloy (iridium, osmium) are determined in individual grains of the Pt-Fe alloy. The individual grains of Pt-Fe alloy have irregular or cubic form. Except Pt and Fe, their composition often includes Cu and, rarely, Pd, uniformly distributed in different parts of the grains. The contents of elements change in the ranges (at.%): Pt from 68.73 to 83.71; Fe 10.33-27.56; Cu 0.04-1.54, and Pd 19.43-20.91. Data about their chemical composition give reason to consider that they are represented mainly by isoferroplatinum and a small part (<10 %) is native platinum. The silicate glass inclusions in them have nearly ideal spherical form and are sized up to 10 mm. The individual grains of Os-Ir-Ru alloy are represented by crystals, formed by strongly polished in the placer hexagonal prism, hexagonal bipyramide and basic pinacoid or by thick plates. Their compositions on the triangle diagram Os-Ir-Ru are disposed in the field of ruthenium. Os-Ir-Ru alloy inclusions lie in the field of iridium and osmium. The iridium inclusions have oval or disk form and size up to 20 mm, and the osmium inclusions are presented by oriented lamellas, up to 5 wide and up to 50 mm long, formed probably from solid solutions. The obtained data shows that PGM from Straldzha graben are presented entirely by alloys characterized by high-temperature magmatic protogenesis and followed by a continuous exogenic transport. They display common features with the PGM from the Priabonian sediments near Novoseltsi village. This is reason to look for common or similar in composition and secondary alterations primary sources. Such can be the described for this region ultramafic volcanic rocks (picrites).

5. Sulfide mineralization in metabasites near Belitsa village, Central Srednogorie (Z. Tsintsov)

Metabasites and the related sulfide mineralization from artificial and native outcrops from the region of Belitsa village, Central Srednogorie, are studied [3]. The metabasite body has not been an object of special investigation and up to now it is considered as an ultrabasite one. The sulfide mineralization is presented by pyrite, chalcopyrite, monosulfide solid solutions (mss) and idaite (?). It is distributed very irregularly in different parts of the body and macroscopically its content falls in the range from 1.0 to 8-10%. The most widespread mineral characterizing the sulfide mineralization is pyrite, which comprises about 94-95%. Pyrite is included in a silica matrix in the form of separate grains or aggregates with irregular or crystal form and is sized up to 2.5 cm. Chalcopyrite is observed mainly as inclusions in pyrite and many rarely in goethite. Idaite (?) is established only in goethite, while mss are observed both in goethite, developed around pyrite, and in the silicate matrix.

The mineral composition and the peculiarity of the sulfides studied give reason to suppose the existence of a genetic connection with the ore mineralization in the neighbouring Panagurishte ore region. The genesis of the studied sulfide mineralization has to be examined in relation to the geological processes, which have caused the formation of this very important ore region in Bulgaria and the followed supergene changes, which most probably are responsible for the formation of idaite (?) only.

6. Late Alpine gold mineralizations in Eastern Rhodopes, SE Bulgaria (I. Marinova)

Next to Byala reka dome and related Lensko and Bely dol gold occurrences (Ann. Rep. 9/2003), and Rosino gold deposit, Kesebir dome is located with numerous attached gold mineralizations Khan Krum, Kuklica, Sinap, Skalak, Surnak, Podrumche, Ludetina, etc. The most interesting of them is Khan Krum deposit because of its good economic parameters. According to literature data, Khan Krum deposit is sediment-hosted, low-angle detachment fault-controlled, epithermal, low-sulfidation, adularia-sericite type, and Upper Eocene in age. Two styles of mineralization were distinguished: a massive, tabular ore body above the tectonic contact, and open space-filling ores along E-W listric faults. Two schemes of mineral sequence are published. The older one recognized five mineral parageneses: 1) quartz-pyrite-marcasite, 2) quartz-pyrrothite-arsenopyrite, 3) quartz-sphalerite-galena, 4) quartz-gold, and 5) quartz-carbonate. The newer one divided the mineralization into four stages: 1) microcrystalline to fine-grained massive or banded quartz with rare pyrite and adularia; 2) economic for gold – millimetre-scale bands of opaline or microcrystalline chalcedony-adularia and electrum, pyrite, rare galena, petzite, hessite; 3) sugary quartz, bands of quartz and bladed calcite; 4) pinkish ankerite-dolomite and siderite, somewhere massive pyrite.

In 2004 a sampling was carried downwards and upwards the low-angle Tokachka detachment fault in "Stenata" outcrop (Khan Krum deposit) by vertical channel samples, covering about a 5-metre interval. Hydrothermally altered metamorphites crop out in the lower plate of fault in this outcrop, whereas pervasively silicified breccio-conglomerates – in the upper plate. The sampled interval was characterised mineralogically [42].

According to our field observations, optical and powder X-ray data the metamorphites below Tokachka fault are strongly faded, softened, argillizated and transformed into pre-ore quartz-kaolinite-adularia-pyrite metasomatites. Kaolinite is detected on all diffraction patterns as major component after quartz. Potassium feldspar (adularia) is also found, but as a minor mineral, everywhere in the altered metamorphites. Electron microprobe analyses of 4 grains showed the following average composition (wt.%): SiO2 64.88, Al2O3 18.20, Fe2O3 0.54, K2O 16.37. Pyrite is not visible by non-aided eye, yet is regularly dispersed in altered metamorphites. It forms cubes sized 0.02-0.30 mm and aggregates in a quartz-kaolinite-adularia matrix. The iron content of metamorphites is about 10 wt.% and due to supergene alteration Fe3+ sharply prevails over Fe2+. Single grains of electrum, silver, galena and pyrite were established in heavy mineral concentrate from the metamorphites.

A pervasive silicification is found developed just above Tokachka fault in Stenata outcrop, replacing completely the Maastrichtian-Paleocene poorly sorted and poorly consolidated polymict breccio-conglomerates and forming the tabular, layer-like silica body mentioned above. The silica is built up mainly of microcrystalline quartz, small amounts of chalcedony and agate varieties, and kaolinite is deposited somewhere in cavities. Electrum and pyrite, pseudomorphosed by goethite, are observed microscopically in the silica in a content usually below 1%, and are the only opaque minerals.

Electrum is micron-sized (usually a few micrometers). It forms single grains and aggregates dispersed in quartz, chalcedony and agate. It becomes visible only on places, where is highly concentrated in thin (below 1 mm) agate bands, forming bonanza ores. On rare occasions it forms intergrowths with pyrite. The Ag concentration in electrum varies from 23.61 to 36.18 wt.% with a fineness from 764 to 637 (based on 17 electron microprobe analyses). The average Au/Ag ratio is 66.81:33.18 (in wt.%) or 2:1. The major part of electrum was deposited simultaneously with quartz, chalcedony, agate and pyrite. Our microscopic study allows us to conclude that the pervasive silicification above Tokachka fault is the first gold-bearing paragenesis in "Stenata" outcrop.

The supergene alteration in both plates of Tokachka fault reveals as formation of X-ray amorphous ochre, goethite and hematite, and sporadically manganite. It seems that a part of kaolinite is also of a supergene origin. The X-ray amorphous ochre is widespread, while goethite forms pseudomorphoses after pyrite in the metasomatized metamorphites and in the pervasive silicification. A small part of goethite is transformed into hematite (proved by X-ray powder diffraction) observed only microscopically as dispersed grains (of a few mm in size) and aggregates.

7. Mineralogical map of Bulgaria, 1:25 000 scale (based on heavy mineral concentrates from stream sediments) (O. Vitov)

The distribution of gold in alluvial sediments in Bulgaria, based on long-term stream-sediment pan-concentrated sampling, was studied [34]. The results revealed that gold is concentrated into main (135°-striking) and minor (45°-striking) stripes. The compiled prognosis maps of gold prospects in Eastern Rhodopes (SE Bulgaria) and in Kjustendil district (Western Bulgaria) confirmed these results. Numerous previous statistical works on gold in Bulgaria showed that it is of polygenic origin, does not prefer any mineral association, and marks zones of intensive hydrothermal activity. Thus, gold-containing stream-sediment samples are indicative for hydrothermal activity and direct to ore districts, ore knots and ore fields (Fig. 1). Mineralogical dividing based on stream-sediment sampling was made and prognosis maps for exploration of various mineral deposits in Eastern Rhodopes and Kjustendil district were compiled as well.

Fig. 1. Gold stream-sediment halos in Kjustendil district and its grouping into two stripes:
Osogovo-Lisec Block one (1-1) and Treklyano village-Kjustendil town-Vlahina Planina one (2-2).

The detailed analysis of the mineralogical knowledge of Kjustendil district showed that till now stream-sediment pan-concentrated sampling has not been carried out in 30% of its territory. On the basis of the available data prognosis maps for prospecting gold, barium, mercury, lead, zinc, tungsten and molybdenum were compiled. These maps revealed that the stream-sediment halos of these elements are highly concentrated into the Treklyano village-Kjustendil town-Sasanski rid-Sgurovo village-Vlahina Planina stripe (Fig. 3). It was shown that fluorite plays an important role in the regional hydrothermal processes there. Mineralogical evidences were obtained, which confirm the geological data of Graff (2001) for an exhumation of Osogovo-Lisec Block in Paleogene and formation of detachment faults of active metallogenic activity (Fig. 2, 3)[92, 141].

Fig. 2. Grouping of scheelite, galena and cinnabar stream-sediment halos in Kjustendil district into the stripes:
Osogovo-Lisec Block (1-1) and Treklyano village-Vlahina Planina (2-2).

Fig. 3. The Treklyano village-Vlahina Planina stripe of maximum mineral diversity
in Kjustendil district based on stream-sediment sampling.

Mineralogical evidences for block structure of Eastern Rhodopes as well as a metallogenic specialization of the blocks were summarized. Prognosis maps for gold, base-metals, tungsten-molybdenum and barium mineralizations were compiled. A particular stripe-pattern of gold arrangement was revealed as well as an attachment of gold to the metamorphic frameworks of the Paleogene volcanogenic depressions [6, 94, 95, Ann. Rep. 10/2005].

The database of stream-sediment pan-concentrated samples taken in Bulgaria was actualized and the mineral diversity of the country, which is the result of the particular spatial distribution of minerals, was summarized. These data appear to be an indication for the probability the prospector to discover a certain mineral in the sampled territory as well as mineralogical indicators of metallogenic specialization of certain regions and of the country as a whole. They also could be used for evaluation the grade of the stream-sediment halos [91, 93, 105, 142].

8. Distribution of cinnabar in alluvial sediments in Bulgaria (O. Vitov, I. Marinova)

The distribution of cinnabar in alluvial sediments in Bulgaria was studied [93, 142] with concern to the high toxicity of mercury, its existence as cinnabar, gold amalgams and mercury drops in alluvial sands and soil, and the presence of numerous mercury and antimony-mercury occurrences and mercury-containing base metal deposits in the country. The data are based on 133 123 stream-sediment samples taken from alluvial sediments in Bulgaria during period 1945-2002.

From all samples 853 contain cinnabar (0.64% or 711 km2 of the territory of Bulgaria) which are prospective for mercury mineralizations. The distribution map of mercury-containing samples shows that cinnabar is concentrated into several regions: Transko and Kjustendilsko Kraishte, Western Balkan, Southern Rila, Eastern Rhodopes, Sakar and Strandja Mts. The contour map of the cinnabar frequences shows the greatest values in Transko and Kjustendilsko Kraishte, Western Balcan and Sakar. Thus, these regions have the highest potential for discoverying cinnabar mineralizations in Bulgaria (Fig. 1a).

Fig. 1. Distribution map of cinnabar in alluvial sediments in Bulgaria: a) in ranks (dots) and in frequencies (lines),
insertions the respective histograms; b) Fourier-model - lines, dots mercury occurrences
and mercury-containing base metal deposits.

The histogram of cinnabar content in the population studied has a well expressed left-side shifted asymmetry (Fig. 1a, insertion a1). The same holds for the cinnabar-frequency histogram (Fig. 1a, insertion a2). These distributions could be interpreted as indicative for the presence of at least two types of cinnabar mineralizations: a cinnabar-poor one (related to base-metal deposits after geological data) and a cinnabar-rich one.

The two-dimensional Fourier-modeling of the data revealed a strip-patterned distribution of cinnabar in Bulgaria (Fig. 1b) as the model has a good correlation with the data. Cinnabar is grouped in two clearly expressed regional stripes: Transko Kraishte-Dospat (135o SE-NW) and Kirkovo village (Zlatograd district)-Madjarovo-Ljubimec-Elhovo (45o NE). It extrapolates stripes in Northern Bulgaria, where sream-sediment data do not exist till now.

The minerals correlated with cinnabar in the alluvial sediments were deduced statistically from the data. They are minerals of base-metal ores and products of their supergene alteration (galena, lead, massicot, malachite), and rock-forming minerals (zircon, anatase and leucoxene). Other correlates of cinnabar are gold, barite and scheelite. Gold is present in five of the seven cinnabar-containing mineral associations, a fact pointing to the presence of epithermal mercury-gold mineralizations (±barite) (Fig. 2). The cinnabar-lead-galena-malachite-massicot association indicates the existence of mercury-containing base-metal mineralizations without gold, like some deposits in Western Balkan.

Fig. 2. Stable mercury-containing mineral associations in alluvial sediments in Bulgaria.

The atmospheric pollution with mercury over the area of Bulgaria drawn out by international mercury monitoring projects binds spatially to power plants (coal combustion), a fact pointing that coal used in the country contain mercury and the latter should be detected and caught before its emitting into the atmosphere. The gases, produced by roasting base metal ores, should also be measured and caught, because these ores contain mercury, as proven by numerous studies.

9. Montmorillonite-cristobalite association in bentonite clays from Bulgarian deposits (A. Ilieva, V. Dimov)

Cristobalite has been described as one of the main non-clay authigenic minerals in the bentonite clays from the Palaeogene volcanic-sedimentary complex in the East Rhodopean-Upper Thracian Palaeogene depression. The structural state of cristobalite and the nature of montmorillonite-cristobalite association in bentonite clays from several Bulgarian deposits were investigated using XRD analysis and TEM [20]. Five samples (fractions below 2 mm separated from suspensions of bentonite clays) were studied in the present work: two varieties of the Kardjali bentonite clays - SB (gray-bluish), and SY (yellow-green), and three white bentonite samples SW-1 (Enchetz vilage, Kardjali district), SW-2 (Dimitrovgrad), and SW-3 (Zlatna livada village, Chirpan district).

The fractions consist mainly of montmorillonite with cristobalite and calcite present as impurities in all the samples. The content of the cristobalite impurity ranges between 2-3 to 12 wt.% in Kardjali bentonites, and up to 30 wt.% in the white bentonite samples. As seen from the XRD-patterns, cristobalite is represented only by two reflections, at 4.06 Е and 2.50 Е. Profile fitting of the diffraction patterns in the range of 19 to 24 2qo (Fig.1) shows the presence of two diffraction maxima: one at about 4.15 Е, broadened and diffuse, corresponding to the disordered opaline matrix or opal-A, and another at 4.054.06 Е. The latter, shifted from 4.04 Е (which is characteristic of the d101 of a-cristobalite) to higher values, is sufficient to distinguish opal-C from a-cristobalite. Such a pattern has been described as typical of the microcrystalline variety of hydrous SiO2 – opal-C. According to the accepted classifications, the cristobalite in the clay fractions of the bentonite studied can be related to the category of opal-C.

Fig. 1. Profile fitting of the powder XRD pattern of sample SW-1

The close association between montmorillonite and cristobalite in the clay fractions is well observed in TEM (Fig. 2). Montmorillonite is represented by isometrical or slightly elongated particles with "cloud-like" diffuse outlines or curled edges. Cristobalite reveals as submicrometric-sized platy grains clustered onto montmorillonitic flakes. Electron probe microanalyses of the montmorillonite-cristobalite "aggregates" show that their chemical composition is predominantly SiO2 (up to 90%). Other components (Al, Mg, Ca, Fe) are characteristic of the montmorillonitic "support".

Fig. 2. Bright field TEM image of the montmorillonite/cristobalite association in the clay fractions
of bentonite, sample SW-1.

The most common selected area electron diffraction (SAED) images, obtained from the "aggregates" described above, consist of polycrystalline diffraction maxima of montmorillonite along the direction [001] and additional spots along the rings, corresponding to dkhl of about 4.1 Е and 2.5 Е (characteristic of low cristobalite), along the direction [111] (Fig. 3a). In some SAED images a breaking of the polycrystalline rings of cristobalite is observed up to forming a discreet spot maxima, corresponding to the single crystalline net in the plane (111)* Fig. 3b. Spot maxima of cristobalite can also be observed, configured symmetrically to the hexagonally disposed spot maxima of montmorillonite (Fig. 3c), obtained along the direction [001]. The latter could be explained by a possible oriented intergrowth of cristobalite and montmorillonite. Analysis of the cristobalitic single crystallite diffraction image implies a possible epitaxial intergrowth of cristobalitic crystallites with atomic planes (112) parallel to the (001) planes of montmorillonite.

Fig. 3. (a,b,c) SAED images of the montmorillonite-cristobalite association

10. LA ICP-MS study of fluid inclusions in quartz from the Yuzhna Petrovitsa deposit, Madan ore field, Bulgaria (B. Kostova, T. Pettke, T. Driesner, P. Petrov, C. Heinrich)

The content of major and trace elements of individual fluid inclusions in quartz from the Yuzhna Petrovitsa hydrothermal PbZn deposit (Madan ore field) were analyzed microthermometrically and by LA ICP-MS in order to better characterization of the ore-forming fluids and their evolution [35]. We found different trends in Th vs. depth for fluid inclusions associated with various stages of mineralization, which quantitatively match predictions from published hydrothermal fluid flow simulations (Fig. 1).

The data indicate that the early quartzpyrite (Q1) association had been formed when the hydrothermal system was still heating up and the temperatures from the early Q1 show a distinctive, nearly linear trend with a gradient of about 40-50єC/100 m. The somewhat later quartzgalenasphalerite main ore stage (Q2) was deposited during the thermal peak under hot hydrostatic head conditions with a temperature-depth distribution representing the fluid's boiling curve. For Q2 only two data sets are available with a vertical difference of 400 m, which indicate an upward temperature drop by 25єC. The thermal gradient would have been much less pronounced than during the Q1 stage and the shallower parts would have been much hotter at this later stage than during Q1. The post-sulphide quartz (Q3) was formed after the thermal peak the temperature during this stage seems rather independent of the mining level, or even indicates a slightly cooler lower part implying an inverse thermal gradient.

Fig. 1. Fluid inclusion homogenization temperatures (Th)
vs. mine level for the three quartz stages (Q1, Q2, Q3)

Fig. 2. Data from Fig. 1 plotted on data from hydrodynamic simulations of a fluid flow above a cooling pluton (modified from Hayba and Ingebritsen, 1997).

Galena and sphalerite precipitated from a slightly acid fluid with a Pb content of about 78 ppm and a Zn content of about 33 ppm at the present-day +668 m level, which represents a paleodepth of about 1200 m (Fig. 2). Precipitation within the vein structure was mainly the result of cooling from about 310єC to 285єC over the investigated 400 m vertical interval.

Ore fluid concentrations of lead and zinc can be used to estimate a minimum time-integrated amount of fluid in the order of 102 km3 that was necessary to form the Madan ore field, which is in a good agreement with values typical of recent hydrothermal systems.

The combination of microthermometric and LAICP-MS results from fluid inclusions with published thermodynamic and hydrodynamic models has provided a new quantitative insight into the thermal and chemical evolution of the hydrothermal system that formed the Yuzhna Petrovitsa PbZn deposit.

11. Results from soil geochemical surveys for ore deposits prospecting in Western and Eastern Bulgaria (I. Marinova, O. Vitov)

The soil geochemical surveys have been widely applied in Bulgaria during the last five decades as a part of prospecting for base- and precious-metal deposits. They have been used at small and large scale in different stages of prospecting. Methodological procedures and outcomes of data processing of soil geochemical surveys carried out in several Bulgarian regions in 10-year period (Western Srednogorie, Kjustendil Kraishte and Eastern Rhodopes) were summarized and a method for evaluation and choice of optimal grid-based framework was presented in brief on an example from Western Balkan [43].

New peculiarities of gold concentrations in soil geochemical dispersion anomalies were revealed in Western Srednogorie: a tendency of equality between the mean content and the standard deviation; Poisson-type of distribution; necessity of correction of the estimated gold resources by a coefficient >1, accounting for the variance of the laboratory analysis and for the natural variance of gold.

On examples from Western Srednogorie and Kjustendil Kraishte, it was shown that two-dimensional Fourier-modeling of soil geochemical data is useful procedure in prognosing of mineral deposits.

The efficiency of soil geochemical surveys for evaluation of regional pollution by heavy metals and subdivision of the pollutants as natural geochemical anomalies and anthropogenic soil pollutions was demonstrated on an example from Kamenitsa depression, Kjustendil region.

It was confirmed that the small scale soil geochemical survey is a reliable approach for evaluation of the ore potential (ore location and expected resources) as well as to direct the prospecting works.

Using a computer simulation, it was shown that efficient prospecting for small gold deposits requires a careful choice of sampling grid conformed to a particular geological setting. Choosing a particular sampling grid the prospector should consider the form, the size and the strike of the expected geochemical anomalies. Our recently offered method for selecting optimal sampling grid (Ann. Rep. 9/2003, 10/2004) is based on "Monte Carlo" simulations of geochemical anomalies of definite form and size corresponding to certain class gold deposits: large, medium and small. Using this method one comprises different grids by four quantitative characteristics – sensitivity, selectivity, representativity and economic feasibility, and then chooses the optimal grid. The first three characteristics account for the probability the sampling grid to hit or not the simulated anomalies with a various number of grid-points. The forth characteristics accounts for the expenses for the soil geochemical survey. The proposed method was tested by computer simulation on Govejda goldfield in Western Balkan, where the deposits are veins of a various strike. The performed tests showed that this method considerably increases the economic efficiency of the soil geochemical surveys.

12. Gold artifacts from the alluvial sediments of Bulgaria - indicators for gold mining and metallurgy during the Bronze Age (Z. Tsintsov)

In two tells near Karlovo town specialists from the National History Museum have found in the second half of 2004 more than 450 golden objects related to the Early Bronze Age. The preliminary visual observations on the size and the morphological features of these finds give reason to state that they are analogous to a part of the numerous (probably numbering tens of thousands) golden objects found by geologists in the alluvial sediments of many rivers in Bulgaria.

Their archeological significance and value are not well clarified yet. The similarity of the alluvial golden artifacts with objects from archeological monuments dated as Early Bronze Age give reason to propose that during this epoch there had been already widely distributed activities connected with mining and metallurgy of gold on the territory of Bulgaria a process differentiated into "mining-metallurgical complexes" [82].


II. ENVIROMENTAL MINERALOGY

13. Mineralogy and geochemistry of coals and their combustion and pyrolysis products (S. Vassilev, Ch. Vassileva)

The phase-mineral and chemical composition of feed coals (FCs) and their bottom ashes (BAs) and fly ashes (FAs) produced in the Soma thermo-electric power station (TPS) - Turkey, was characterized. FCs are high-ash subbituminous Soma coals abundant in moisture and Ca and depleted in S. The inorganic composition of FCs includes mainly calcite, quartz, kaolinite, illite, muscovite, chlorite, plagioclase, gypsum, and pyrite, while the phase-mineral composition of BAs and FAs includes mainly glass, quartz, char, mullite, plagioclase, calcite, and portlandite. The results for 57 elements studied show that Ca > Nb > Cs > (V, Li) have significantly higher contents in FC ashes than the respective Clarke values for coal ashes. Most of the trace elements, in particular As, Bi, Cd, Ge, Pb, Sn, Tl, and W, are more abundant in FAs, while BAs are enriched in Ca, Cs, Fe, Ho, Mn, P, Sc, Se and Tb. Significant quantities (11-59%) of elements initially present in FCs, namely S > Sb > Sn > Ta > Mo > Bi > Zn > Ni > Na > (Lu, Tm) > B, were emitted by stack emissions and not captured by the cleaning equipment in the Soma TPS [87]. Six fractions were recovered from FAs produced in the Soma TPS and their phase-mineral and chemical composition was also characterized. The following fractions were isolated: (1) char concentrates (CCs); (2) light fractions (<1 g cm_3) (LFs); (3) water-soluble residues (WRs); (4) magnetic fractions (MFs); (5) nonmagnetic coarse-grained fractions (>63 µm) (NCFs); and (6) nonmagnetic fine-grained fractions (< 63 µm) (NFFs). Possible environmental concerns are related mainly to the trace elements mobility in WRs, LFs, and CCs, while the potential utilization directions are connected mostly with the composition of MFs, WRs, CCs, LFls, and NFFs [88]. The variations in FA composition between Unit B1 and Unit B5 of the Soma TPS were also studied. Slightly greater contents of lime, portlandite, and gehlenite and lower contents of quartz have been determined in Unit B1-4 than in Unit B5-6. Results of elemental analysis showed that most of the trace elements have greater concentrations in FA from Unit B1-4, except Ca and U, which have greater contents in FA from Unit B5-6. The mean values in both units indicate that some volatile element concentrations, notably As, B, Bi, Cd, Pb, and Zn, increase from coarse to finer particle size fly ashes [23]. Mass balance of major and trace elements in two group boilers (Unit B1-4 and Unit B5-6) of Soma TPS was calculated with two methods. The results show that S, Ta, Hg, Se, Zn, Na, Ca in Unit B1-4, and Hg, S, Ta, Se, P in Unit B5-6, have volatile behaviour during coal combustion in Soma TPS. It also implies that Sb and Tb in Unit B1-4 and Sb in Unit B5-6 have relatively high retention effects in the combustion residues from the Soma TPS [111].

The phase-mineral and chemical composition of heavy concentrates (HCc) and fly ash residues (IFAs) recovered from five fly ashes (FAs) produced in four large Spanish TPSs was characterized. The HCs were separated by sink-float separation in bromoform, while the IFAs are residues after the isolation of ceramic cenosphere, salt, magnetic, char and heavy concentrates. The HCs recovered are in the range 0.02-0.28% and their phase-mineral composition commonly includes aluminosilicate glass, hematite, magnetite, larnite, quartz, periclase, mullite, corundum, lime, char, melilite, rutile, plagioclase, wollastonite, ferrian spinel, and anhydrite. Numerous accessory minerals of Ba, Ce, Cl, Cr, Cu, F, Fe, La, Mn, P, Pb, Th, Ti, Y, and Zr, are also typical components of HCs. These fractions are enriched in As, Ca, Cr, Cu, Gd, Mg, Mn, Mo, Fe, Ni, Pb, S, Se, Ti, V, Zn, and Zr in comparison with the FAs. The isolated IFAs are in the range 71.5-97.1% and their phase-mineral composition normally includes aluminosilicate glass, mullite, quartz, char, kaolinite, plagioclase, cristobalite, wollastonite, hematite, anhydrite, K-feldspar, melilite, and corundum. The contents of most elements in IFAs are similar to FAs, however Ag, Ba, Cl, Cs, Ge, Mo, S, Sb, and Sc are significantly depleted in these residues. The IFAs have an improved composition in comparison with the FAs because they are: more homogeneous and finer-grained products, abundant in pozzolan and inert constituents, and depleted in harmful components. Some genetic features, properties, possible environmental concern, and potential utilization directions related to the HCs and IFAs are described. A basis for advanced, multicomponent, wasteless, and environmentally safety utilization of various FAs is also discussed [89].

The mineral and chemical compositions and some trace element contents (As, Ba, Cr, Mn, Mo, Sb, Th, U, and V) in coal and coal ash samples from the Huaibei coalfield in China were studied. This high-volatile bituminous coal has low moisture and S contents, moderate ash yield and high calorific value. The coal ash is abundant in aluminosilicates as the contents of the Fe oxides are relatively similar to the sum of alkaline-earth oxides. The minerals identified in coal are mainly quartz, kaolinite, pyrite and calcite, and, to a lesser extent, dolomite, ankerite, illite, chlorite, opal, feldspars, marcasite, gypsum, melanterite, and hematite. Common minerals in the high-temperature ash (815oC) are initial quartz and newly formed anhydrite, lime, hematite, and Ca-Mg silicates. Some trace elements, such as Cr > Th > V > Mo in the coal and Cr > Th > V in the coal ash, are enriched in comparison with the Clarke concentrations [40].

The present state of the methods commonly used for characterization of phase, mineral and chemical composition of fly ashes from coal-fired power stations is described and summarized. The application of various methods such as macroscopic observations, ashing procedures (high-temperature and low-temperature), physical separations (density, magnetic, particle size, froth flotation, and electrostatic), chemical leaching, sequential physical and chemical treatments, as well as optical microscopy (reflected and transmitted), electron microscopy (scanning and transmission), X-ray diffraction, differential thermal and thermogravimetric analyses, Mossbauer and infrared spectroscopy, and different chemical analyses are briefly discussed. A short critical overview on the advantages and limitations as well as certain recommendations for application of the above-listed methods are done. Some considerations about the practical use of data for the fly ash composition are also discussed [85].

Bulgarian lignites (Maritza East, Maritza West, Sofia) were gradually heated under air from 100°C to their fluid ash-fusion temperatures (1200-1300°C) via 100°C intervals and the behaviour of their inorganic matter (IM) was studied. The pre-existing minerals and newly formed inorganic phases in the oxidation and combustion products (OCPs) were identified and the behaviour of 38 minerals and phases was described. The lignites reveal low detrital abundance and high authigenic mineralization with sulphide-sulphate or carbonate tendencies. The IM of lignites is composed mainly of quartz, kaolinite, gypsum, calcite, and pyrite, while the other minerals identified have subordinate occurrence. The IM of OCPs includes also various newly formed phases such as glass, amorphous clay material, mullite, hematite, Ca and Ca-Mg silicates, cristobalite, tridymite, magnetite, Ca and Mg oxides-hydroxides, anhydrite, and others originating from the heating of these lignites or the storage of their OCPs. The physico-chemical processes and temperatures that result in the formation of new phases in OCPs are described. The relationships between the ash-fusion behaviour and chemical and mineral composition of the lignites are also discussed [90].

The achievements of studies conducted during the last ten years period (1995-2004) on the mineralogy and geochemistry of coals and their combustion and pyrolysis products were summarized [86].


14. Crystal matrix of Synroc-type synthesis in hot pressing installation (I. Donchev, V. Genov, F. Dipchikov, N. Zidarov)

A crystal matrix for incorporation in its crystal lattice of guest ions, namely – Sr, Nd, Sm, Eu is synthesized. The synthesis is based on preliminary calculated mixture of oxides (shiht) for directed crystallization with the aim to obtaining an artificial analogue of the meteoritic mineral hibonite. The shiht is prepared from CaCO3, SrCO3, Al2O3, TiO2, Nd2O3, Sm2O3, and Eu2O3. Hibonite (calcium hexaaluminite) has a crystal chemical formula of the type (Ca, Sr, REE) [Al,Ti]12 O19 and possesses a very high temperature and chemical durability.

An installation for hot pressing in vacuum of powdered materials (Crystallox) is used for the synthesis. From a well-homogenized in planetary mill shiht tablets with diameter of 20 mm are pressed and heated in graphite crucible to temperatures of 1000oC, 1100oC and 1300oC, for 30 min and 1 hour. Pressures up to 100 Mpa are applied.

Fig. 1. Powder XRD pattern of the as-syntesized hibonite, obtained by directed crystallization in Crystallox hot pressing installation. CuKa, diffractometer DRON 3M, 15-80o 2q. 350 – 800oC

In the polarizing microscope the obtained materials display microcrystalline structure with submicroscopic size of the particles and without glazing. XRD analysis proved only the presence of calcium hexaaluminite (hibonite) whith d-spacing and intensities of the peakes displaying very small deviations, which correspond to the data for iron-bearing hibonite – PDF 38-0469, ICDD – (Fig. 1).


15. Arsenic speciation, solubility and mobility in deposits from copper production waste storage (N. Lihareva)

The ponds for storage of waste from the metallurgical activity are a source for environmental contamination. In order to solve some ecological and technological problems, a study is carried out in the pond for deposition of wastes that result from treatment of acid water from copper production in MDK "Pirdop". Studies concerning the arsenic content, distribution and mobility are presented [38].

A sequential three stage extraction procedure for arsenic compounds was applied and optimized according to the nature of the analyzed products. During the first stage the content of water-soluble arsenic compounds was determined, during the second the HCl-soluble forms, and during the third the compounds soluble in sodium hydroxide. The optimum conditions for leaching arsenic from sediments (sample weight, concentration and volume of extractants, time of treatment) were established for each fraction.

Speciation studies for determining As (III) and As (V) were carried out in the obtained arsenic extracts. The ability for the proposed sequential extraction procedure to specify the valence forms of inorganic arsenic was evaluated using model samples with added As (III) and As (V) and the recovery of spikes was assessed. It was found that oxidation of As (III) and processes of sorption and sedimentation of As (V) proceed upon dissolution. A depth profiling was performed of the content of diverse As forms in two sites. The content of water-soluble As does not exceed 7.3% of the total As in the sediments, As (III) being lower than 7.4% of the extracted As. The bulk of arsenic compounds (above 78% As) is dissolved in 2M HCl, and As (V) was found to be more than 94% of the extracted arsenic. The analytical features of the procedure are: precision evaluated through the repeatability (w > 0.96) and accuracy estimated by the recovery (above 93%) calculated on the basis of a twice repeated analysis of a series of nine samples.

One can see from this study that arsenic in the deposits is predominantly in the HCl soluble fraction. This shows that the pollution of water and the environmental risk by sediment leaching are possible only in decreasing pH water (acid rains or acid waste water).


III. MODELING AND MODIFICATION OF MINERAL SYSTEMS

16. Geometrization of the language of mineralogy (V. Penev, N. Zidarov, B. Zidarova)

Based on the analysis of the evolutionary stages of the development of different sciences, the problem for the geometrization of the language of mineralogy is grounded in a general form as a main evolutionary task in the forthcoming, qualitatively new evolutionary stage of development of mineralogy. The way for solving this problem is outlined by formulating a system of four basic tasks to be solved during the next stage of the development of the language of mineralogy. As a result of the logical analysis of the foundations of the language of mineralogy, the system of categories "structure", "composition" and "construction" is logically correctly defined. The relations of these categories with the cognitive and classical structural paradigms and the notions internal energy of a thermodynamic system, order, symmetry, etc., are analyzed. The conceptual scheme for an entirely mathematical spatial representation of arbitrary chemical (including mineralogical) structures, both ordered and disordered, is briefly represented. The main geometrical results obtained are represented, analyzed and interpreted in the terms of mathematical functions. The use of the developed original conceptual scheme for an entirely mathematical coordinate representation of arbitrary chemical and mineral structures is demonstrated on the examples of wurtzite [57], rutile [58], fluorite and pyrite [115].

It is shown that:


17. Synthetic kenyaite as catalyst support for hydrocarbon combustion (Yu. Kalvachev, V. Kostov-Kytin, S. Todorova, K. Tenchev, G. Kadinov)

Synthetic kenyaite is prepared in the system K2OSiO2H2O [34, 129]. It is modified with cobalt and platinum and characterized by powder XRD, SEM, TG-DTA, TPR (temperature programmed reduction) and FTIR spectroscopy. Cobalt is loaded on kenyaite using ammonia method and classical impregnation in order to obtain catalysts for complete oxidation of n-hexane and benzene. The catalysts prepared by ammonia method display better performance due to finer dispersion of the metal particles on the surface of the support. The temperature dependences of the complete benzene and n-hexane oxidation over catalysts prepared by both methods are shown on the Figure. The only detectible reaction products in all studied samples were H2O and CO2.

Fig. 1. Dependence of the conversion with temperature in the reaction of complete oxidation of:
a. benzene; b. hexane.

The samples can be compared according to the temperature for 95% hydrocarbon conversion or according to that one for maximum conversion in cases this value has not been reached. The following order of activity in the reaction of complete benzene oxidation is established: Pt/Ken (640 K) » Co+Pt/Ken-AM (640 K) Co/Ken-AM (700 K)>Co+Pt/Ken-I (705 K, 90%) > Co/Ken-I (723 K, 76%). The values in brackets for the last two samples show maximum conversion reached in the studied temperature interval 298-723 K. The row of activity in the complete hexane oxidation is as follows: Co/Ken-AM (633 K)>Co+Pt/Ken-AM (723 K)>Co+Pt/Ken-I (723 K, 93%) >Co/Ken-I > (723 K, 89%) > Pt/Ken (703 K, 83%). As seen 95% conversion has not been attained with samples prepared by impregnation. Despite the lower cobalt concentration, the monometallic Co/Ken-AM is more active than the catalysts prepared by impregnation in the above reactions. This sample demonstrates highest activity in the case of deep hexane oxidation.


18. Thermal and structural investigation of hydrotalcite phases and their transformations (N. Petrova, S. Bakardjieva, Ts. Stanimirova, D. Nihtianova, U. Kolb, D. Kostadinova)

Mixed oxide products of thermal decomposition of natural and synthetic hydrotalcite samples were investigated using SEM, TEM, in situ XRD and BET surface area analysis. The obtained Mg-Al oxide is stable in the temperature range 350-800oC (Fig.1a) and is characterized by a high porosity and specific surface area between 325 and 421 m2/g, a value 10 times higher than that of the initial hydrotalcite samples. These peculiarities explain the potential of the mixed oxide products as alkaline catalysts and catalyst supports.

Fig. 1a. Hydrotalcite Mg-Al oxide transformation.
in situ XRD data

350-800oC

Fig. 1b. Hydrotalcite Mg-Al oxide transformation.
TEM morphological and diffraction data.

The pseudomorphic character of the hydrotalcite mixed-oxide transformation was demonstrated by TEM morphological and diffraction data (Fig. 1b), i.e. the texture of cubic nano-sized periclase-like oxide crystals preserves a layer character of the initial hydrotalcite structure.[64, 65, 140].

The layered double hydroxides (LDH) have a great potential as precursors of metal nanoparticles on a basic support. These metal supported materials offer interesting outlooks for catalytic or magnetic applications. Supported metal particles were prepared by reduction of metal (Ni2+, Sn2+/Cu2+) colloids/ LDH nanocomposites following two different routes: (i) thermal reduction at 800oC upon a H2 flow, and (ii) soft chemistry treatment by sodium borohydride as a reducing agent.

The changes during the thermal decomposition of the samples were registered by DTA-TG, while the structural transformations – by XRPD. The metal particle size and morphological peculiarities were determined by TEM. It was shown that the thermal reduction leads to structural transformations and to a fine control of the particle size (5 nm for Ni-particles). However, the initial layer structure is retained after the NaBH4 reduction and the size of metal particles varies between 3-30 nm for Ni- and between 4-20 nm for Sn-Cu. The study will continue with the optimization of the process of metal-LDH intercalation and the control of metal particle size [133].


19. Mass-transport processes in silicate melts under external fields: model investigation of basaltic melts subjected to a constant electric field with axial symmetry (J. Muchouvski, N. Zidarov, M. Tarassov)

The mass-transport processes in basaltic melts under an external constant electrical field with axial symmetry are investigated. It is supposed that such a model describes (as first approximation) the mass-transport inward the boundary zone of magmatic chambers, where significant temperature gradients between the magma and surrounding rocks cause a thermo-electromotive force and ion-migration [51]. The experiments consist in electrolysis of molten basalt in an electrochemical cell, representing thin hollow platinum cylinder (anode) and axially disposed platinum wire (cathode). The external potential Uext is being varied in the range 0.1-5 V, while the melt temperature between 1450 and 1604 K. The time and temperature dependences of non-stationary mean current density through the cell are studied at constant voltages and the results are related to those obtained for rectangular ceramic cells with two parallel platinum electrodes. It is established that:

1. The cell polarization, Дзcell, is cathodic, of the concentration type, increasing as y = a + bxc (c > 1) with the augmentation of the external voltage, and linearly on rising temperature. It becomes much higher under a field with axial symmetry than a field with linear symmetry at 1.5 V Ј Uext Ј 5 V. Most probably, such a result is due to increasing differences in the "end-effects" contribution for the two types of electrical field.

2. The time for attainment of a stationary state (stationary current) decreases with the rise of temperature's rise: from 600 s at T = 1600 K, to more than 8000 s at T= 1440 K (Fig. 1). This results from rapidly increased mobility and diffusion coefficient of ions that determine the higher current values through the cell at the applied voltage. At temperature significantly higher (by 160 K) than the transition one and after approximately 1000 s of the start of electrolysis, the current begins to increase slightly, that is explained by the appearance of kinetic limitations for ionic reduction.

Fig. 1. Dependence time vs. total current density in a basaltic melt in electrochemical cell
with axial symmetry under an external voltage of 1 V (mean field intensity of 1.37 V/cm):

a) up to 1000 s;

b) up to 8000 s.

3. The temperature dependences of the specific electrical conductivity and viscosity are affected insignificantly by the electrical field symmetry: the activation energies for the processes with axial and linear symmetry are nearly the same being equal to 41.6 ± 1.5 kcal/mol and 48.2 ± 2.2)kcal/mol, respectively.

4. During sharp withdrawal of the cell from the heating zone, the heat is radiated through the surface of the melt that supposes a very quick bulk glassing and insignificant redistribution of its components.


IV. SYNTHESIS, COMPOSITION, STRUCTURE, AND PROPERTIES OF MINERALS AND NEW MATERIALS

20. Local structure and dynamics in functional materials (B. Mihailova, L. Konstantinov, V. Kostov-Kytin, Yu. Kalvachev, O. Petrov, M. Tarassov, R. Petrova)

The understanding of the relationship between the properties and the local structural irregularity of functional materials is a key problem in modern solid state science. The challenge to optimise the functionality of advanced materials via tuning the nanoscale atomic arrangements provokes considerable scientific efforts into design and structural characterization of novel materials.

One class of multi-functional materials are relaxor-ferroelectrics: materials with extraordinary high dielectric permittivity, electrooptic and electrostrictive coefficients and exhibiting memory effects of multiple aging, which determine their wide range of applications as capacitors, actuators, non-volatile RAM, etc. Complementary utilization of X-ray diffraction and phonon spectroscopy gives insight into the nanoscale structural species in relaxors. The analysis of two model representatives, PbSc0.5Ta0.5O3 and PbSc0.5Nb0.5O3, showed the key role of point defects (doping in the perovskite-type B-position and defects in the oxygen sub-system) for the preferred incipient polar clusters formed near the Curie range and, hence, on the nanoscale domain texture developed on cooling [49].

Besides the common applications of zeolite-type materials (catalysis, ion exchange, separation processes), layered and microporous titanosilicates are very promising to be used as host matrices in composite materials with applications in optoelectronics, non-linear optics, batteries and sensors. The utilization of infrared, Raman and 29Si MAS NMR spectroscopic methods allowed analysing the structural species formed in organic template-free alkali-titanium-silicate systems prior to hydrothermal treatment. The results revealed the relationship between the composition of the synthesis mixture and the predominant type of atomic clusters in the amorphous precursors as well as the trends in the crystalline phase formation upon hydrothermal treatment of the corresponding gels [31].

Zeolite Beta (BEA) is a high-silica large-pore molecular sieve having a three-dimensional pore system and exhibiting an outstanding catalytic performance. The most peculiar property of zeolite Beta is its highly disordered framework: the structure is considered as an intergrowth of two end-members, polymorph A and B, with extremely high stacking fault frequency. The interlayer stacking faults in zeolite Beta affects the regularity of the pore structure along the c direction and may influence the diffusion processes and selectivity. The degree of interlayer faultlessness in nanoparticles of zeolite Beta cannot be estimated properly by standard diffraction methods. Raman spectroscopic study of various samples of BEA- and BEC framework topology clarified the effect of interlayer stacking disorder on phonon modes of BEA-type materials and revealed the Raman signals which can be used for estimating the degree of periodicity faults along the c direction. It is shown that zeolite Beta nanocrystals (ca. 15 nm) embedded into a mesoporous silica matrix exhibit a high degree of interlayer stacking faultlessness [48].


21. Single crystal structure analysis of Sr-bearing chabazite from Kayryaka quarry, Bourgas region, Bulgaria, and its Sr-exchanged form (R. Petrova, A. Ivanov, M. Kadiyski, O. Petrov, V. Kostov-Kytin, M. Tarassov)

Occurrences of natural Sr-containing chabazite are rare. Sr-chabazite has been described in Kayryaka quarry, Bourgas region, Bulgaria, during a previous study [66]. The aim of the present investigation is to prepare a Sr rich chabazite via cation exchange and to study the location and coordination of the extra-framework Sr by the single-crystal X-ray method.

Kayryaka quarry is located at about 2 km SW of Chernomorets village, Bourgas region. It is built up of monzonites, part of the Rossen pluton. The monzonites contain pegmatite bodies, having central hydrothermal zones built up of quartz, albite, epidote, calcite, chalcopyrite, chlorite, laumontite, chabazite, etc.

Fig. 1. Chabazite crystal from Kayryaka quarry,
Bourgas region, Bulgaria.

The investigated chabazite samples were collected from the hydrothermal zone of the pegmatites. The morphology, color and size of the crystals were determined macroscopically and under binocular microscope. For the single crystal X-ray experiments, specimens with maximum transparency and suitable size and shape (nearly cubic fragments, approximately 0.066x0.066x0.066 mm long) were selected. Part of the crystals was subjected to ion exchange with Sr2+ aiming to increase the strontium quantity and localize it in the structure. The exchange was performed in water solution of strontium nitrate Sr(NO3)2 for three days at 60°C and four days at room temperature.

The chemical composition of the natural and exchanged Sr-chabazite was quantitatively analyzed by an electron microprobe (Philips SEM-515 with an EDAX PV 9100/70 EDS system). X-ray data collection of natural and exchanged chabazite crystals was performed at room temperature with monochromatic Mo radiation (λ=0.710730Å) using single crystal diffractometer EnrafNonius CAD-4 where diffracted intensities are detected by a scintillation counter.

Structure refinement of natural and exchanged Sr-chabazite was carried out with the program SHELX-97. Cation sites and positions of oxygen atoms from water molecules were localized by analysis of different Fourier maps.

The studied chabazite crystals are well-shaped rhombohedra (Fig. 1) or twins along and {0001}. The crystals reach up to 20 mm in size. Most of them display two distinct zones: inner zone, with rusty-brown coloration, ranging from yellowish-brown to dark brown, and outer zone, which is yellowish or colorless.

The electron microprobe analysis yielded Ca1.44Na0.29K0.18 Sr0.12Cu0.04(Si8.32 Al3.61Fe0.06)O24.nH 2O for natural and Ca0.87K0.18Sr0.68Cu 0.04(Si8.24Al3.70Fe 0.06)O24.nH2O for the Sr-exchanged chabazite, based on 24 oxygen atoms. It appears that after seven days of ion exchange the sodium cations have completely exchanged as confirmed by chemical analysis. Ca atoms are just partially substituted by Sr. Data also show an increase of the SrO content from 1.53 wt.% in natural chabazite to 8.57 wt.% after the exchange.

Unit cell parameters (a=b=c=9.388Å, α=β=γ=94.395°) were established from 22 reflections in the range 20.08<θ<21.81. The structure refinement of natural and Sr-exchanged crystals was based on 1224 unique reflections in the range 2.18<θ<25.96, defining the  symmetry group with Z=4.

After the last refinement the reliability factors were as follows: R=0.1022, wR=0.3166 and GooF=1.1430 for the natural chabazite and R=0.1055, wR=0.3637 and GooF=1.401 for Sr-exchanged chabazite, respectively.

Main cation sites remain the same in both natural and Sr-exchanged form of chabazite (Fig. 2). Occupancy factors have changed as follows: after ion exchange Sr occupies preferably position I and some Sr ions go to position II; Ca quantity in position III (the double hexagonal cage) slightly increases in Sr-exchanged chabazite.

Fig. 2. Crystal structure representation of chabazite: a) perspective projection along the pseudo-triad axis [111];
b) projection along [001], small spheres represent extra framework cation sites.

a

b

Single crystal X-Ray diffraction method was used to investigate natural Sr-bearing chabazite and its Sr-exchanged form. Results are comparable with previous studies and show incomplete substitution of Ca atoms by Sr. After the exchange Sr ions are incorporated preferably in position I (at the top of the big chabazite cage) and position II in the centre of the big cavity. Although not fully exchanged, the chabazite structure shows ion exchange selectivity for Sr2+ at the expense of Na+ and Ca2+. Further exchange forms of chabazite from Kayryaka quarry are under preparation and structural investigation.


22. Organic crystals with potential optical activitiy (R. Petrova, B. Shivachev, K. Kossev)

Recently, there is considerable interest in the synthesis of new materials with large second-order optical nonlinearities (NLO) both for study of new NLO phenomena and for their potential use in applications including telecommunications, optical computing, optical data storage and optical information processing. In general, NLO coefficients of organic crystals are superior to those of inorganic materials and thus nowadays organic crystals are extensively studied. In order to possess the NLO properties one of the prerequisites for a material is its atoms or molecules to have a noncentrosymmetric arrangement. Thus, in collaboration with our colleagues from the Institute of Organic Chemistry BAS by using the concepts of molecular and crystal engineering we are attempting to obtain new organic crystals, which would have noncentrosymmetric arrangement, large nonlinear susceptiblility, and wide transparency range.

Fig. 1.

 

Fig. 2.

 

Fig. 3.

 

Fig. 4.

 

Fig. 5.

Fig. 6.

 

Fig. 7.

As a result, several newly synthesized crystalline phases have been obtained. Suitable crystals for X-ray diffraction were isolated for six of them, namely: 2-(3-Benzoyl-1-pyridinio)-3,4-dioxocyclobutenolate [27] (Fig. 1), 2-{3-[(E)-(3,4-Dimethoxyphenyl)ethenyl]-5,5-dimethylcyclohex-2-enylidene}malononitrile [26] (Fig. 2), 6-O-Acetylcodeine [28] (Fig. 3), codeinone [112] (Fig. 4) (R)-4-Benzyl-3-((S)-2-tricyclo[3.2.1.03,6]oct-2-ylacetyl)-oxazolidin-2-one [24] (Fig. 5), (3RS,4RS)-3-(2-Furyl)-2-phenetyl-4-(pyrrolidin-1-ylcarbonyl)-3,4 -dihydroisoquinolin-1(2H)-one [67] (Fig. 6) [1-(Hydroxyethylammonio) propyl]phosphonate [71] (Fig. 7). Crystal structure determination showed that noncentrosymmetric arrangement is present in four of them [3-6] provoking a subsequent investigations for optical activity, which is now in progress. In addition, compounds 5 and 7 were studied for biological activity but the obtained results were not promising.

23. Crystal structures of spiro-5'-hydantoine compounds (B. Shivachev, R. Petrova)

During the years the hydantoine and hydantoine derivatives have been studied mainly in relation with their biological activity. Systematic investigations, carried out on such series of compounds (e.g. synthesis, complexation, crystal structures, biological activity), require the participation of specialists from different scientific fields. The observed interesting properties of spiro-5'-hydantoine compounds associated with the lack of information for their mono and dithio derivatives as well as their complexation ability were between the main arguments to start an extensive study involving scientists from different research fields in several institutions: the University of Chemical Technology and Metallurgy, the Chemical Faculty of Sofia University, the Technological college Russe, and the Central Laboratory of Mineralogy and Crystallography "Acad. Ivan Kostov" (CLMC). The study of such compounds is partially financed by the Bulgarian National Science Fund and the crystal structures of the newly synthesized compounds are performed in the CLMC.

Fig. 1. polymorph I


Fig. 2. polymorph II

 

 

 

 


The crystal structures of seven cycloalkane-spiro-5'-hydantoine were determined. The crystal structure of 3aminocyclohexan-spiro-5'-hydantoine (1) has been published [73]. The molecules of (1) crystallize in two different polymorphs from two different solutions. Both crystal modifications crystallize in the P21/c space group with the difference that in polymorph I two symmetrically equivalent molecules are present, while the crystal structure of polymorph II is built up by only one molecule. The three-dimensional packing and hydrogen bonding stabilizing the structures of both polymorphs are represented in Fig. 1 and 2. One should pay attention to the different role played by the cyclohexane and hydantoin parts in the crystal structure stabilization. The crystal structures of the cycloheptan-spiro-5'-hydantoine and 3aminocyclohexan-spiro-5'-hydantoine with phenilborate have been refined and will be published the next year.

Fig. 3. Structural motif involved in the crystal structures of dithiospiro-5'-hydantoine derivatives of cyclopentan, cyclohexan, cycloheptan and cyclooctan.

A series of four dithio spiro-5'-hydantoine derivatives (cyclopentan, cyclohexan, cycloheptan cyclooctan) has been investigated. The results concerning crystal structures of the these compounds are in press [116]. It is worthy to note that all four structures are build up by identical topological structural units linking the molecules trough S…H-N hydrogen bonds (Fig. 3).


24. Real structure study of Vitosha tourmaline by computer simulated HRTEM images (V. Dimov, Z. Vergilov, B. Kostova, I. Vergilov)

Tourmalines from Vitosha Mt. show growth inhomogeneities, which indicate a crystallization of a metastable phase and sub-solidus exsolution during the next crystal cooling. Direct analysis by transmission electron microscopy (TEM) gives complex information about their chemical and structural inhomogeneities [12]. Different local chemical compositions in two tourmaline zones a brown (ferruvite) and a green (schorl-dravite), were determined as follows:

X(Na0.55Ca0.52) 1.07Y(Mg2.06Fe2+ 0.76Fe3+0.11)2.93 Z(Al4.32Fe2+0.45 Ti0.20Fe3+1.03) 6B3(Si5.91Ti0.09 )6O27.31(OH)3.69

X(Na0.86Ca0.08) 0.94Y(Mg1.66Fe2+ 0.7Fe3+0.64)3 Z(Al5.7Fe2+0.34 )6.04B3(Si5.96Al 0.04)6O27(OH)3.60 .

Different plane symmetry of the two zones was observed via the phase-contrast change in high-resolution transmission electron microscopy images (HRTEMI) (Fig.1a, 2a). This presumes different symmetry space groups for the diverse domains in the two zones.

Fig. 1. HREMI of brown (feruvite) zone:
a - experimental; b - computer simulated.

Fig. 2. HREMI of green (schorl-dravite) zone:
a - experimental; b - computer simulated.

A structural model for these domains was proposed depending on the Z position occupancy. HRTEMI of a polydomain structure with different symmetry space groups in both tourmaline zones were simulated (Fig.1b, 2b) by constructing a super-cell of the three most probable domain structures. The correspondence between the experiment and the simulated HREMI confirms the correctness of the hypothetical structural models of green and brown tourmalines.

A low symmetry structural model is proposed, resulting from two tourmaline enantiomorphic domain structures, suggesting that the growth mechanism depends mostly on the local chemical composition.


25. TEM investigation of Na4Zr2Si5O16 .H2O (U. Kolb, D. Nihtianova, V. Kostov-Kytin, Y. Kalvachev)

Na4Zr2Si5O 16.H2O was obtained under static hydrothermal conditions [135]. This is a new compound with unknown crystal structure. The phase was investigated by TEM (EM 420 Philips, Philips Tecnai 12) and powder X-ray diffraction (DRON 3M). The unit cell parameters were determined by a series of tilts in SAED mode and powder X-ray diffraction.

Fig. 1. Three coordinate crystallographic sections of Na4Zr2Si5O16.H2O, obtained by AED.

Powder diffraction data (a = 5.752 Å, b = 9.392 Å, c = 13.096 Å, space group Cmc21) was confirmed by the electron diffraction patterns shown in Fig. 1. In zone [100] which was taken from a thicker crystal than the other zones extinctions along c* can not be seen clearly but every second reflection is weaker. In b* direction, every odd row is absent (0kl: k = 2n) showing a b glide plane perpendicular to a or a C-centering. In zone [010] for all h0l the rule h = 2n holds. There are clear extinctions along c* (l = 2n) implying a 21 axis along c* or a c-glide plane perpendicular to a. In zone [001] for all hk0 the rule h+k = 2n holds which can originate from a n-glide plane perpendicular to c or a C-centering. As a result, the only possible space group, where C-centering and 21 axis along c* are found, is the space group Cmc21.


26. Atomic arrangements in amorphous sodium titanosilicate precursor powders (V. Kostov-Kytin, B. Mihailova, Yu. Kalvachev, M. Tarassov)

Infrared, Raman and 29Si MAS NMR spectroscopic methods are applied to analyse the relationship between the chemical compositions of the initial synthesis gels, predominant type of atomic arrangement in the amorphous precursors obtained from the dried gels and the favoured crystalline titanosilicate phases formed upon hydrothermal treatment [31]. In the investigated template-free system the Na2O/TiO2 ratio in the initial gel plays a key role in the synthesis of titanosilicates. This ratio influences the arrangement of the precursor clusters in the initial mixture prior to the hydrothermal treatment and, subsequently, on the type of the framework topology of the run products.

The spectroscopic data reveal that for gels with a lower Na2O/TiO2 ratio the precursor amorphous powders possess a lower degree of polymerisation of the SiO4 species than that of the first crystalline products. That means that the hydrothermal treatment induces the homocondensation of SiO4 groups. Contrary, for gels with a higher Na2O/TiO2 ratio the hydrothermal treatment enhances the fragmentation of the Si-O system in the final run product as compared to the amorphous precursors.

Within the investigated range of Na2O/TiO 2 ratios of the synthesis mixture, frameworks with five-coordinated titanium are obtained at the lowest (3.7) and highest (9) ratio values, while six-coordinated Ti4+ is predominant in structures prepared at intermediate ratio values. Layered and microporous titanosilicates crystallize as a pure phase at lower Na2O/TiO2 ratios (approx. 7 in the studied system), while dense titanosilicates are preferentially formed at higher alkalinity.

The high sensitivity of the framework-topology type to variations in the Na2O/TiO2 ratio allows precise tuning and control in the preparation of titanosilicate phases with tailored pore system and functionality.


27. Hydrothermal synthesis, Rietveld refinement, and photoluminescent properties of Eu silicate with apatite-type structure (S. Ferdov, R. A. Sa Ferreira, Z. Lin)

Apatites play a very important role in biomaterials and have many different applications including good luminescent properties, nuclear waste management potential use as solid electrolytes, sensors and oxygen pumps. Up to now two main methods for synthesis of REE oxyapatites are known by solid-state reaction and sol-gel method. Now we present results on structural characterization, photoluminescent properties, and, for the first time, mild hydrothermal synthesis of europium oxyapatite, Na0.3Eu9.24Si6O 26 (hexagonal, P63/m, a=b=9.4815(9), c= 6.9140(7) Å, Z=1). The chemical composition was proven by EDS analyses and the structure was refined by powder X-ray diffraction data. The performed Rietveld refinement (Fig. 1) showed that the sodium atoms fill one (6h) out of two metal positions present in the structure with an occupancy factor of 5%. The remaining places of this site are occupied by europium. Position 4f is partly occupied but only by europium (88.5%) The hydrothermal method allows inclusion of Ln+3 ion in the framework and by this way fine-tuning of the photoluminescent properties is performed by dilution of the europium content with gadolinium. The photoluminescence features were investigated both in steady state and time resolved modes. For the undiluted sample, evidences of concentration quenching will be discussed later, whereas the Eu3+ dilution in the Gd-based material contributes to an enhancement of the emission quantum yield.

Fig. 1. Experimental and simulated powder XRD pattern of Na0.3Eu9.24Si6O 26.


28. Structural changes in opal from Stambolovo deposit, Bulgaria after thermal treatment (A. Yoleva, P. Djambazov, S. Djambazov, O. Petrov)

The structure of Bulgarian opal from volcanogenic-sedimentary flint rock (Stambolovo deposit, Haskovo region) is studied for establishment of the phase transformations of this opal after thermal treatment at temperatures 200, 400, 600, 800, 1000, 1100, 1200, 1300, and 1400oC [144].

The chemical composition of the studied opal sample is given in Table 1. It is evident that the content of coloring admixtures is very low and the sample is quite pure opal.

Table 1. Chemical composition of opal from Stambolovo, Bulgaria.

Oxides SiO2 Al2O3 TiO2 Fe2O3 MgO CaO Na2O K2O SH2O
Opal 96.62 0.59 0.01 0.03 0.05 0.11 0.05 0.15 8.23

The obtained XRD, DTA/TG and IR-spectroscopy data confirm that the opal sample from Stambolovo deposit, Haskovo district, is typical opal-CT with quartz phase of less than 5 wt.%. The natural opal is very pure with low contents of Fe, Al, and Ti. During thermal processing it is structurally stable to high temperatures (Fig. 1 and 2). Above 1350oC it is structurally transformed to the more stable opal-C (Fig. 3).

Fig. 1. XRD patterns of thermally treated opal.

Fig. 2. IR spectra of thermally treated opal.

Fig. 3. XRD patterns of opal heated at 1100, 1200, 1300 and 1400oC.

The crystallite size of this opal is in the range of the nanometer scale. The crystallite size of cristobalite increases from about 10 to 15 nm when heated at 1400oC. The crystallite size of tridymite lowers with temperature - from 7 to 3 nm at 1300oC and at 1400oC this peak disappears. This indicates a destruction of tridymite and partial recrystallization of the glass all this resulting in formation of dominant cristobalite phase at 1400oC.

As a conclusion we may state that the studied opal is appropriate to be used as a raw material for production of water glass by chemical methods. Because of its high purity and reactivity this opal may be used in the production of glasses, frits and glazes.


29. Brookite correlation between morphology and photoactivity (S. Bakardjieva, N. Petrova)

Nanocrystalline TiO2 has received much attention during the recent years in expectation of being used as a photocatalyst for environmental cleaning. A phase-pure brookite of high crystallinity was prepared via a reaction of solution of urea and titanium (III) chloride at 70oC under ambient pressure. The resulting "flower-type" agglomerates (~300 nm) (Fig. 1a) are composed of brookite nanocrystals (10 nm) (Fig. 1b), which are stable up to ~350oC in terms of their phase purity and morphology. The ash-prepared sample has a high specific surface area of 460 m2/g, which rapidly decreases after a transformation to pure rutile at 900oC. The brookite powder shows a good photocatalytic activity under UV radiation. [119].

Fig. 1. Transmission electron micrographs of:

a) "flower-type" brookite agglomerates;

b) composed brookite nanocrystals.


30. Growth of ternary fluoride crystal compounds Ca1-xSrxF2: stoichiometric effect on optical properties (I. Mouchovski)

The importance of the ternary fluoride crystal compounds of type Ca1-xMexF2 (Me = Ba, Sr) as optical material for manufacturing stepper lenses to produce next generation integral circuits gave reasons for further development of a reliable technology of growing crystals in the group Ca1-xMexF2 (Ann. Rep. No 10/2004). Chemically purified fluorspar with low contents of rare earths (total amount < 20 ppm) and Merck-suprapur grade SrF2 are used as starting components for fluoride compounds. Portions of these metal fluorides are high-temperature processed in vacuum and PbF2-vapor for removing the most of the adsorbed oxygen contaminants from their particles. The obtained high-density precursors together with definite amounts of PbF2 and ZnF2 additives are loaded in a crucible with 1 central (2" diam.) and 9 peripheral (1" diam.) cameras. The growing is carried out by the BS-method in dynamic argon atmosphere with five nines purity, as the multi-cameral crucible is put into the modified furnace unit of BSGS, apparatus that has been used in CLMC the last two decades for growing optical CaF2 crystals with different grades. The axial canals of internal crucible lids possess low gas-permeability that predetermines slow Knudsen diffusion of gaseous-vapor components through the canals. The crystals stoichiometry is set by varying the x-part of SrF2 from 0.045 to 0.493. The grown bulls are mono-crystalline, colorless and visibly transparent. The bulls are fine-annealed to minimize the residual internal stresses: the applied three different regimes lead to lowering of the birefringence measured by polariscope-polarimeter PKS-250 below 5 nm/cm, except structural defects on the boundaries of some isolated inhomogeneous regions. The spectral characteristics of 5 mm thick optical windows prepared from both the upper and the lower parts of the bulls are registered by spectraphotometer Cary 5EVarian with photometric accuracy 0.1% transmission and wavelength accuracy 0.1 nm in VIS and 0.4 nm in NIR (8003300 nm). It is established:

1. Insignificant effect of varying Ca Sr ratios (x-parameter) on light-transmission in VIS and NIR and several alterations in UV (Fig. 1), related to different position and abundance of definite optical-active centers based on rare-earth ions embedded in the crystalline structure.

2. High degree of optical homogeneity in radial direction as regards light transmission in the whole spectrum available for measuring from 190 nm (UV) to 3300 nm (NIR).

3. Iso-transmission curves in л-x dependence, outlining regions of stable distinction in spectrum, thus suggesting specificity of the quasi-stoichiometric phases in crystalline structure.

The key outcome is that the developed in the CLMC optimized technological schemes for growing perfect optical CaF2 crystals may be efficiently applied for growing crystalline Ca1-xSrxF2 compounds.

Fig. 1. Transmission spectra for 5 mm thick optical windows,
1" diameter, finished from Ca1-xSrxF2 bulls,
at different ratio of starting components (0.045 Ј x Ј 0.943).


V. D.Sc. THESESES

31. Mineralogy and Geochemistry of Coals and Solid Waste Products from Coal Combustion (S. Vassilev)

The purpose of this dissertation is to characterize and systematize the mineralogy and geochemistry of various coals worldwide and their combustion solid waste products (SWP) from thermo-electric power stations (TPSs) [9]. The methodical approach includes a parallel investigation of coals, SWP, soils, water and plants for a number of TPSs. A complex of methods, namely macroscopic observation, separation procedures (sieving, sink/float separation in water and heavy liquids, froth flotation, magnetic separation, handpicking under microscope, others), thermal treatment (80-1600°C), optical microscopy, SEM, TEM, XRD, DTA-TGA, various chemical analyses, ash-fusion test, producing of dry water-soluble residues, and others were used. The major fundamental and applied contributions of the present dissertation include:

1. Feed coals, their low-temperature and high-temperature laboratory ashes, intermediate (bottom ashes, slags, fly ashes) and final (bottom ash/fly ash and slag/fly ash mixtures) SWP from coal combustion, waste water; plants from the disposal sites of SWP, and soils near TPSs were studied simultaneously for the first time based on a systematic approach and complex of methods.

2. The mineral and chemical composition of coals and coal ashes from 54 coal deposits of Bulgaria, Australia, Canada, China, Japan, Russia, South Africa, Spain, Turkey, Ukraine and USA was identified and characterized. Contents and modes of occurrence of 111 mineral species or mineral groups and inorganic phases in these coals were summarized and systemized. The genetic peculiarities of detrital and authigenic (syngenetic and epigenetic) minerals and their alteration products were also described. The concentrations and modes of occurrence of 73 elements in coals and coal ashes were determined. The relationships between the inorganic composition of coals and their rank, ash yield and ash-fusion temperatures were clarified.

3. The phase-mineral and chemical composition of SWP generated from coal combustion in 16 TPSs of Bulgaria, Spain and Turkey was identified and characterized. Contents and modes of occurrence of 96 mineral species or mineral groups and phases were summarized and systemized. The phase transformations in inorganic matter of coals during combustion in TPSs and the mechanism of SWP formation were elucidated. The concentrations and modes of occurrence of 73 elements in SWP from these TPSs were determined.

4. Six potentially useful and/or dangerous products from Bulgarian, Spanish and Turkish fly ashes were sequentially recovered and characterized. A scientific basis for the multicomponent, wasteless and environmentally safety utilization of fly ashes was given.

5. Components and reasons for the environmental pollution (air, water, soils and plants) of the areas surrounding TPSs were also determined.

INTERINSTITUTE PROGRAMS


POSTDOCTORAL FELLOWS AND VISITING SCIENTISTS


RESEARCH TOPICS, ANNOUNCED FOR INTERNATIONAL PARTNERSHIP COLLABORATION


PUBLICATIONS AND REPORTS AT CONFERENCES AND LOCAL MEETINGS


PUBLISHED ARTICLES AND REPORTS

1. Arishtirova, K., L. Dimitrov, A. Predoeva, P. Kovacheva, Z. Pacheva. 2005. Ultrastable mesoporous materials, modified with BaO, as catalysts for the oxidative methylation of toluene with methane. – Nanoscience & Nanotechnology, 5, Heron Press, Sofia, 126-129.

2. Baicheva, O., A. Damianova, D. Salkova, N. Lichareva, N. Nikolova. 2005. Vanadium and its components as a possible method against plants-parasitic nematodes. – Experimental Pathology and Parasitology, v. 8, 3, 123-129.

3. Banushev B., Z. Tsintsov. 2005. Sulfide mineralization in metabasites near Belitsa village, Central Srednogorie. Univ. of Mining and Geology "St. Ivan Rilski, Sofia", v. 48, part I, Geology and Geophysics, 11-16. (in Bulgarian with English Abstracts)

4. Campos, A. A., C. R. Silva, M. Wallau, L. Dimitrov, E. A. Urquieta-Gonzбlez. 2005. Recrystallisation of SBA-15 into ZSM-5/SBA-15 composites. Studies in Surface Science and Catalysis, J. Cejka, N. Zilkova, P. Nachtigall (Eds.), Elsevier, v. 158, 573-580.

5. Ganev, V. 2005. Electron states of Fe3+ in hematite and goethite – DFT calculations on Fe-O clasters. In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 191-193. (in Bulgarian)

6. Georgiev, V., O. Vitov. 2005. Heavy concentrate prognoses in prospecting of ore deposits in the Eastern Rhodopes. Geology and mineral resources, 1-2, 31-37. (in Bulgarian with English Abstracts)

7. Damyanov, Z. 2005. Paleohydrothermal ore-formation system of the Kremikovtsi complex-ore deposit genetical features and practical consequences. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 77-88. (in Bulgarian)

8. Damyanov, Z. 2005. Anniversary scientific session "10 years Central Laboratory of Mineralogy and Crystallography "Akad. Ivan Kostov". Mining and Geology, 60, 4, 41-42. (in Bulgarian)

9. Dimov, V. 2005. Ways for identification and structural characterization of microphases by TEM. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 195-199. (in Bulgarian)

10. Dimov, V., N. Khaltakova. 2005. Determination of structural parameters of minerals and synthetic phases in tem using saed images obtained from rotation of single crystals around a crystallographic axis. – Ann. L'Univ. Sof., 1- Geol., 97, 107-115.

11. Dimov, V. I., P. K. Vitanov. 2005. Formation of porous silicon: Electron microscope investigation. – Journal of Applied Physics, v. 98, 3, 1-9.

12. Dimov, V., Z. Vergilov, B. Kostova, I. Vergilov. 2004. Real structure study of Vitosha tourmaline by computer simulated HRTEM images. – Ann. L'Univ.Sof., 1- Geol., 96, 121-130.

13. Donchev, I. 2005. Scientific-practical aspects of the research in CLMC-BAS. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 17-22. (in Bulgarian)

14. Donchev, I., F. Dipchikov, B. Zidarova, N. Lihareva, N. Zidarov. 2005. Synthesis of a "Synroc" material with simulative additions of Sr, Sm and Nd and testing of its chemical durability. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 151-154. (in Bulgarian)

15. Donchev, I., N. Lihareva, Y. Tzvetanova. 2005. A new deposit of celestine in the Lower Cretaceous sediments near Krousheto village, Gorna Oryahovitza municipality. – Ann. L'Univ. Sof., 1- Geol., 97, 45-53. (in Bulgarian with English Abstracts)

16. Doshkova, D., D. Kaisheva, B. Mihailova, M. Gospodinov. 2005. Crystal growth, structure and dielectric properties of ferroelectric mixed Pb2ScTaxNb1-xO 6 single crystals. – Journal of Optoelectronics and Advanced Materials 7, 447-450.

17. Ferdov, S., V. Kostov-Kytin, O. Petrov. 2005. Synthesis and characterization of microporous titanosilicates. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 155-158. (in Bulgarian)

18. Ferdov, S., V. Kostov-Kytin, O. Petrov. 2005. Synthesis and Characterization of Nanosized Na GTS-1. – Nanoscience & Nanotechnology, 5, Heron Press, Sofia, 167-169.

19. Ferdov, S., U. Kolitsch, O. Petrov, V. Kostov-Kytin, C. Lengauer, E. Tillmans. 2005. Synthesis and crystal structure of a new microporous zirconosilicate MCV-2. – Microporous Mesoporous Materials 81, 79-86.

20. Ilieva, A., V. Dimov. 2005. Montmorillonite-cristobalite association in bentonite clays from Bulgarian deposits. – Proc. of the Jubilee International Conference "80 years BGS", Sofia, 71-74. (in English with Bulgarian Abstracts)

21. Kaisheva, D., D. Doshkova, B. Mihailova, M. Gospodinov. 2005. Dielectric behaviour of Sn doped and annealed ferroelectric lead scandium tantalate single crystals. – Journal of Optoelectronics and Advanced Materials, 7, 443-446.

22. Kalvachev, Yu., Kostov-Kytin, V.. 2005. Gold-based catalysts for environmentally important reactions. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 163-166. (in Bulgarian)

23. Karayigit, A., Y. Bulut, X. Querol, A. Alastuey, S. Vassilev. 2005. Variations in fly ash composition from the Soma power plant, Turkey. – Energy Sources, 27, 1473-1481.

24. Kavrakova, K. I., P. S. Denkova, R. P. Nikolova. 2005. Kharasch-type addition of 3-bromoacetyl-2-oxazolidinones to norbornadiene. Stereoselective Lewis acid promoted. – Tetrahedron: Asymmetry, 16, 1085-1089.

25. Kolb, U., D. Nihtianova, J. Li, D. Kovacheva, I. Nikolov, V. Nikolov. 2005. Studying the crystal structure of single crystals of NaAl(WO4)2 – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 185-188. (in Bulgarian)

26. Kolev, T., D. Yancheva, B. Shivachev, R. Petrova, M. Spiteller. 2005. 2-{3-[(E)-(3,4-Dimethoxyphenyl)ethenyl]-5,5-dimethylcyclohex-2-enyli dene}malononitrile. – Acta Cryst., E61, 550-552.

27. Kolev, T., D. Yancheva, B. Shivachev, R. Petrova, M. Spiteller. 2005. 2-(3-Benzoyl-1-pyridinio)-3,4-dioxocyclobutenolate. – Acta Cryst. C61, 213-215.

28. Kolev, T., R. Bakalska, B. Shivachev, R. Petrova. 2005. R. 6-O-Acetylcodeine. – Acta Cryst., E61, 25822584.

29. Konstantinov, L. 2005. Vibrational and electronic states in disordered and defected multicomponent materials. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 59-62. (in Bulgarian)

30. Koseva, N., A. Bogomilova, I. Tzaneva, K. Kossev, R. Georgieva, K. Troev. 2005. Polyphosphoesters with potential application in pharmacy. – Proceeding of the XV National symposium of Polimers, October 6-7, Sofia, 75-76.

31. Kostov-Kytin, V., B. Mihailova, Yu. Kalvachev, M. Tarassov. 2005. Atomic arrangements in amorphous sodium titanosilicate precursor powders. – Microporous and Mesoporous Materials, 86, 223-230.

32. Kostov-Kytin, V., Yu. Kalvachev. 2005. Hydrothermal synthesis and characterization of new sodium zirconosilicates. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 159-162. (in Bulgarian)

33. Kostov-Kytin, V., J. Macicek, V. Breskovska, R. Petrova. 2005. Lead-antimony chlorine sulphosalts synthesis, crystal chemistry and prognosis for new structures. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 147-150. (in Bulgarian)

34. Kostov-Kytin, V., Yu. Kalvachev. 2005. Synthesis of kenyaite in Zr-containing reaction medium. – Compt. rend. Acad. bulg. Sci., 58, 2, 185-190.

35. Kostova, B., T. Pettke, T. Driesner, C. A. Heinrich, P. Petrov. 2004. LA ICP-MS study of fluid inclusions in quartz from the Yuzhna Petrovitsa deposit, Madan ore field, Bulgaria. – Schweizer. Miner. Petr. Mitt., 84/1-2,25-36.

36. Kouzmanov, K., A. v. Quadt, I. Peytcheva, C. Harris, C. A. Heinrich, E. Rosu, G. O'Connor. 2005. Rosia Poieni porphyry Cu-Au and Rosia Montana epitermal Au-Ag deposits, Apuseni Mountains, Romania: Timing of magmatism and related mineralization. – Geochem., mineral. and petrol., 43, 113-117.

37. Kunev, B., V. Petkova, D. Paneva, D. Mitova, E. Manova, I. Mitov. 2005. Mechanochemical and thermomechanochemical treatment of Pyrite Concentrate – particle size effects. – Nanoscience & Nanotechnology, 5, Heron Press, Sofia, 163-166.

38. Lihareva, N. 2005. Arsenic solubility, mobility and speciation in the deposits from a copper production waste storage. – Microchemical Journal, 81, 177-183.

39. Lihareva, N., O. Petrov, Y. Tzvetanova. 2005. Determining the forms of presence of Cd, Cr and Ni in precipitates from purification stations and sediments. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 119-122. (in Bulgarian)

40. Liu, G., S. Vassilev, L. Gao, L. Zheng, Z. Peng. 2005. Mineral and chemical composition and some trace element contents in coals and coal ashes from Huaibei coal field, China. – Energy Conversion and Management, 46, 2001-2009.

41. Macheva, L., R. Titorenkova, N. Zidarov. 2005. Kyanite-staurolite-garnet-bearing schists from Ograzhden mountain, SW Bulgaria – metapelites or orthoschists. – Proc. of the Jubilee International Conference "80 years BGS", Sofia, 138-141. (in English with Bulgarian Abstracts)

42. Marinova, I. 2005. Hypogene and supergene minerals in "Khan Krum" gold deposit, "Stenata" site (Eastern Rhodopes), at Tokachka detachment fault contact. – Proc. of the Jubilee International Conference "80 years BGS", Sofia, 168-171. (in English with Bulgarian Abstracts)

43. Marinova, I., O. Vitov. 2005. Results of soil geochemical surveys in prospecting for ore deposits in Western Srednogorie, Kjustendil Kraishte, Eastern Rhodopes and Western Balkan. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 111-118. (in Bulgarian)

44. Majano, G., S. Mintova, O. Ovsitser, B. Mihailova, T. Bein. 2005. Zeolite Beta nanosized assembles. – Micropor. Mesopor. Mater., 80, 227-235.

45. Mihailova, B. 2005. Lokal structure and phonon anomalies in nano-sized regions of functional materials. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 63-68. (in Bulgarian)

46. Mihailova, B., M. Gospodinov, B. Gьttler, F. Yen, A. P. Litvinchuk, M. N. Iliev. 2005. Temperature-dependent polarized Raman spectra of HoMn2O5 and TbMn2O5. – Phys. Rev., B. 71, 172301/1-172301/4.

47. Mihailova, B., S. Mintova, K. Karaghiosoff, T. Metzger, T. Bein. 2005. Non-destructive identification of colloidal molecular sieves stabilized in water. – J. Phys. Chem., B 109, 17060-17065.

48. Mihailova, B., V. Valtchev, S. Mintova, N. Petkov, A.-C. Faust, T. Bein, 2005. Interlayer stacking disorder in zeolite Beta family. A Raman spectroscopic study. – Phys. Chem. Chem. Phys, 7, 2756-2763.

49. Mihailova, B., U. Bismayer, B. Gьttler, M. Gospodinov, A. Boris, C. Bernhard, M. Aroyo. 2005. Nanoscale phase transformations in relaxor-ferroelectric lead scandium tantalite and lead scandium niobate. – Zeitschrift fьr Kristallographie, 220, 740-747.

50. Mincov, I., B. Shivachev, T. Troev, V. Ganev, A. Liolios, Sp. Dedoussis, M. Chardalas. 2005. Temperature dependence study of crystallization of Fe78Si9B13 amorphous alloy by positron lifetime method and DTA. – Proc. of Second Balkan Conference on Glass Science and Technology, v.1, 258-263.

51. Muchovski, J., M. Tarassov, N. Zidarov. 2005. Experimental study of mass-transport processes in basaltic melts at a constant electric field. – Proceedings of "XV Russian workshop on experimental mineralogy", Syktyvkar, June 22-24, 2005, 88-90. (in Russian)

52. Muchovski, J., V. Penev, V. Genov. 2005. Synthesis of optical crystals with a wide applicability. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 173-178. (in Bulgarian)

53. Nihtianova, D., J. Li, U. Kolb. 2006. Electron crystallography in mineralogy and materials research, Electron Crystallography. Novel Approaches for Structure Determination of Nanosized Materials. – In: Electron Crystallography. Novel approaches for structure determination of nanosized materials, T.E.Weirich, J.L. Labar, X. Zou (eds.), NATO Sci. ser. II Math., Phys. and Chem., vol. 211, Springer, 421-433.

54. Nikolova, R. 2005. X-ray structural analysis and phase identification of new materials. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 69-74. (in Bulgarian)

55. Nikolova, R., B. Shivachev. 2005. Crystal structure of 3Pb (COOH)2. 13tu.H2O. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 189-190. (in Bulgarian)

56. Penev, V. 2005. Geometrization of the fundaments of chemistry basic results. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 131-138. (in Bulgarian)

57. Penev, V., N. Zidarov, B. Zidarova. 2005. Geometrization of the language of mineralogy. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 123-130. (in Bulgarian)

58. Penev, V., N. Zidarov, B. Zidarova. 2005. Logical analysis and mathematical formalization of the foundations of the languageof mineralogy a premise for its geometrization. – Ann. L'Univ. Sof., 1 - Geol., 97, 85-96. (in Bulgarian with English Abstracts)

59. Petkova, V., B. Kunev, D. Paneva, I. Mitov. 2005. Application of mechanochemical activation followed by thermal treatment for utilization of pyrite concentrates. – Chemistry for sustainable development,, v. 13, 351-358. (in Russian)

60. Petkova, V., Y. Pelovski, I. Dombalov, K. Tonsuaadu. 2005. Thermochemical investigations of natural phosphate with ammonium sulphate additive. – Journal of Thermal Analysis and Calorimetry, v. 80, 701-708.

61. Petkova, V., Y. Pelovski, I. Dombalov, P. Kostadinova. 2005. Influence of triboactivation conditions on the synthesis in natural phosphate - ammonium sulphate system. – Journal of Thermal Analysis and Calorimetry, v. 80, 709-714.

62. Petkova, V., Y. Pelovski, V. Hristova. 2005. Thermal analysis for identification of E-beam nanosize amonium sulfate. – Journal of Thermal Analysis and Calorimetry, v. 82, 813-817.

63. Petrov, O. 2005. Modeling and modification of mineral systems a basis for creation of new materials. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 41-46. (in Bulgarian)

64. Petrova, N., P. Tzvetkov, Ts. Stanimirova, G. Kirov. 2005. Nano-sized mixed (Mg-Al) oxide products of the hydrotalcite decomposition. – Nanoscience & Nanotechnology, 5, Heron Press, Sofia, 174-177.

65. Petrova, N. , Ts. Stanimirova. 2005. Thermal, sorption and crystal chemical features of hydrotalcite and hydrotalcite-like phases. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 167-172. (in Bulgarian)

66. Petrova, R., A. Ivanov, M. Kadiiski, O. Petrov, V. Kostov-Kytin, M. Tarassov. 2005. Single crystal structure analysis of Sr-bearing chabazite from Kayryaka quarry, Bourgas region, Bulgaria, and its Sr-exchanged form. – Proc. of the Jubilee International Conference "80 years BGS", Sofia, 75-78. (in English with Bulgarian Abstracts)

67. Petrova, R., B. Shivachev, K. Kossev, M. Stoyanova, S. Angelova. 2005. (3RS,4RS)-3-(2-Furyl)-2-phenethyl-4-(pyrrolidin-1-ylcarbonyl)-3,4-dihydro isoquinolin-1(2H)-one. – Acta Cryst. (2005). E61, 2248-2250.

68. Peytcheva, I., A. v. Quadt, B. Kamenov, R. Nedyalkov, S. Stoykov, Z.. Ivanov, K.. Kouzmanov. 2005. Magma sources and precise timing of Cu-Au deposits in Central Srednogorie. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 97-102. (in Bulgarian)

69. Peytcheva, I., A. v. Quadt, R. Titorenkova, N. Zidarov, E. Tarassova. 2005. Skrut granitoids from Belassitsa Mountains, SW Bulgaria: Constraints from isotope-geochronological and geochemical zircon data. – Proc. of the Jubilee International Conference "80 years BGS", Sofia, 109-112. (in English with Bulgarian Abstracts)

70. Radev, D. D., M. Marinov, V. Tumbalev, L. Konstantinov. 2005. Mechanically activated self-propagated high-temperature synthesis of nanometer-structured MgB2. – Physica C, 418, 53-58.

71. Shivachev, B., R. Petrova, K. Kossev, K. Troev. 2005. [1-{2-Hydroxyetilammonio|propyl] phoshonate. – Acta Cryst, E61, 134-136.

72. Shivachev, B., E. Kashchieva, Y. Dimitriev. 2005. DFT calculations of cluster formation in vitreous B2O3. – Phys. and Chem. of Glasses, 46/2, 253-255.

73. Shivachev, B., R. Petrova, E. Naydenova. 2005. Dimorphism in 3'-aminocyclohexanespiro-5'-hydantoin. – Acta Cryst., C61, 523-526.

74. Stoykov, S., I. Peytcheva, A. v. Quadt, R. Moritz, M. Frank, D. Fontigniй. 2004. Timing and magma evolution of the Chelopech volcanic complex (Bulgaria). – Swiss Bull. Miner and Petrol., 84, 1/2, 101-118.

75. Tarassov, M. 2005. Chemical and structural transformations of tungsten-iron, and iron mineral phases under exogene conditions. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 47-50. (in Bulgarian)

76. Tarassov, M., E. Tarassova. 2005. Occurrence, chemical composition and electron probe dating of accessory REE-Y-Th-U minerals from Igralishte granite pluton (Ograzhden blok, Serbo-Macedonian massif). – Proc. of the Jubilee International Conference "80 years BGS", Sofia, 91-94. (in English with Bulgarian Abstracts)

77. Tarassov, M., E. Tarassova, I. Peytcheva, A. v. Quadt. 2005. In situ electron-microprobe dating of monazites from Igralishte and Klissura granites. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 107-110. (in Bulgarian)

78. Tarassova, E., M. Tarassov. 2005. Accessory allanites as indicators of the magmatic processes in Skrut granitoids, Belassitsa mountain. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 93-96. (in Bulgarian)

79. Titorenkova, R. 2005. Heterogeneity of zircon from high-grade metamorphic rocks, Ograzhden and Maleshevska Mountains, Serbo-Macedonian massif. – Ann. L'Univ. Sof., 1- Geol., 97, 35-43.

80. Titorenkova, R., L. Macheva. 2005. Morphological. textural and chemical characteristics of zircon in melanocratic enclaves and their host metagranites (Ograzhden mountain, Serbo-Macedonian massif, SW Bulgaria). – Proc. of the Jubilee International Conference "80 years BGS", Sofia, 150-153. (in Bulgarian with English Abstracts)

81. Tsintsov, Z. 2005. Platinum-group minerals from sediments in Straldja graben Eastern Srednogorie. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 89-92. (in Bulgarian)

82. Tsintsov, Z. 2005. Gold artifacts from the alluvial sediments of Bulgaria – indicators for gold mining metallurgy during the Bronze Age. – Proc. of the Jubilee International Conference "80 years BGS", Sofia, 217-220. (in English with Bulgarian Abstracts)

83. Tsintsov, Z., B. Banushev. 2005. Agates from the Aheloy occurrence, Bourgas district. Mineral composition and structural features. Mining and geology, 8, 41-45. (in Bulgarian with Russian and English Abstracts).

84. Vassilev, S. 2005. Mineralogy and geochemistry of coals and solid waste products from coal combustion. D.Si. Thesis, Sofia, 73 p. (in Bulgarian)

85. Vassilev, S., C. Vassileva. 2005. Methods for characterization of composition of fly ashes from coal-fired power stations: a critical overview. – Energy and Fuels, 19, 3, 1084-1098.

86. Vassilev, S., C. Vassileva. 2005. Mineralogy and geochemistry of coals and products of their burning and pyrolisis. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 33-40. (in Bulgarian)

87. Vassilev, S., C. Vassileva, A. Karayigit, Y. Bulut, A. Alastuey, X. Querol. 2005. Phase-mineral and chemical composition of composite samples from feed coals, bottom ashes and fly ashes at the Soma power station, Turkey. – International Journal of Coal Geology, 61, 35-63.

88. Vassilev, S., C. Vassileva, A. Karayigit, Y. Bulut, A. Alastuey, X. Querol. 2005. Phase-mineral and chemical composition of fractions separated from composite fly ashes at the Soma power station, Turkey. – International Journal of Coal Geology, 61, 65-85.

89. Vassilev, S., R. Menendez. 2005. Phase-mineral and chemical composition of coal fly ashes as a basis for their multicomponent utilization. 4. Characterization of heavy concentrates and improved fly ash residues. – Fuel, 84, 973-991.

90. Vassileva, C., S. Vassilev. 2005. Behaviour of inorganic matter during heating of Bulgarian coals. 1. Lignites. – Fuel Processing Technology, 86, 12-13, 1297-1333.

91. Vitov, O. 2005. A map of heavy-mineral concentrates in Bulgaria. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 51-58. (in Bulgarian)

92. Vitov, O. 2005. Mineralogical knowledge and dividing of Kustendil region (Western Bulgaria) based on stream sediment surveys. – Proc. of the Jubilee International Conference "80 years BGS", Sofia, 178-181. (in Bulgarian with English Abstracts)

93. Vitov, O., I. Marinova. 2005. Distribution of cinnabar (HgS) in alluvial sediments in Bulgaria. – Compt. rend. Acad. bulg. Sci., 58, 11, 1287-1290.

94. Vitov, O., V. Georgiev. 2005. Characteristics of the gold distribution in stream sediment pan concentrated surveys from Eastern Rhodopes, SE Bulgaria. – Ann. L'Univ. Sof., 1- Geol., 97, 97-106. (in Bulgarian with English Abstracts)

95. Vitov, O., V. Georgiev. 2005. Block structure of the Eastern Rhodopes and mineral composition of the heavy minerals concentrates samples. – Geology and mineral resources, 6, 37-42. (in Bulgarian with English Abstracts)

96. Von Quadt, A., I. Peytcheva. 2005. The southern extension of the Srednogorie type Upper Cretaceous magmatism in Rila-Western Rhodopes: Constraints from isotope-geochronologycal and geochemical data. – Proc. of the Jubilee International Conference "80 years BGS", Sofia, 113-116. (in English with Bulgarian Abstracts)

97. Von Quadt, A., R. Moritz, I. Peytcheva, C. A. Heinrich. 2005. Geochronology and geodynamics of Late Cretaceous magmatism and Cu-Au mineralization in the Panagyurishte region of the Apuseni-Banat-Timok-Srednogorie belt (Bulgaria). – Ore Geology Review, 27, 95-126.

98. Wallau, M., L. Dimitrov, E. A. Urquieta-Gonzбlez. 2005. Mesoporous carbon, prepared by nanocasting of MCM-41 and MCM-48 nanoparticles. Studies in Surface Sci. and Catal., M. Jaronec, A. Sayari (Eds.), Elsevier, v. 156, 535-542.

99. Yaneva, V., V. Petkova, I. Dombalov. 2005. Structural changes and phase transitions of Syrian phosphorite under tribochemical activation. "Soilscience", t. XL, 15-20. (in Bulgarian with English Abstracts)

100. Yaneva, V., V. Petkova, I. Dombalov. 2005. Influence of the tribochemicalactivation upon the solid phase synthesis in the systemSyrian phosphorite-ammonium sulphate. - "Soilscience", t. XL, 9-14. (in Bulgarian with English Abstracts)

101. Yaneva, V., V. Petkova, I. Dombalov. 2005. Structural transformation after mechanical activation of natural phosphorite originating from Syria. Chemistry for sustainable development, v. 13, 305-311. (in Russian)

102. Zidarov, N. 2005. 10th Anniversary of Central Laboratory of Mineralogy and Crystallography "Acad. Ivan Kostov". Journal of the Bulgarian Academy of Sciences, v. 3, 71-77. (in Bulgarian).

103. Zidarov, N. 2005. Development and achievements of CLMC-BAS for the period 1995-2005. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 9-16. (in Bulgarian)

104. Zidarov, N., B. Zidarova. 2005. Mineral systems: composition, conditions and processes of formation, alteration, and interaction. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 23-32. (in Bulgarian)

105. Zidarov, N., V. Kostov-Kytin, O. Vitov, I. Marinova, V. Stoilov. 2005. The Project "National Mineralogical Database level of realization". – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 139-142. (in Bulgarian)

106. Zidarov, N., J. Muchovski, M. Tarassov. 2005. Redistribution of chemical components in basaltic melts upon a constant electric field. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 179-184. (in Bulgarian)

107. Zidarov, N., Y. Tzvetanova. 2005. The preserved mineral diversity in Bulgaria in the CLMC collection. – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 143-144. (in Bulgarian)

108. Zidarova, B., N. Zidarov. 2004. Main elements of the common geogenetic model for deposits of the Fluorite Ore Formation in Bulgaria. Rev. Bulg. Geol. Soc., 64, 1-3, 55-66. (in Bulgarian with English Abstracts)

109. Zidarova, B., I. Peytcheva, A. v. Quadt, N. Zidarov. 2005. Geochemical and Nd-Sr characteristics of fluorite from "Chiprovtsi-East". – In: Zidarov, N., Z. Damyanov, B. Zidarova, I. Donchev, M. Tarassov, O. Vitov (eds.). Jubilee volume "Ten years Central Laboratory of Mineralogy and Crystallography Acad. I. Kostov", BAS, Acad. publishing house "Marin Drinov", Sofia, 103-106. (in Bulgarian)


PUBLICATIONS IN PRESS

110. Kamenov, B., Y. Yanev, R. Nedialkov, R. Moritz, I. Peytcheva, A. v. Quadt, S. Stoykov, A. Zartova. Petrology of Late-Cretaceous island-arc ore-magmatic centers from Central Srednogorie, Bulgaria: magma evolution and paths. – Int. J. Earth Sci.,

111. Karayigit, A. I., Y. Bulut, G. Karayigit, X. Querol, A. Alastuey, S. Vassilev, C. Vassileva. Mass balance of major and trace elements in coal-fired Soma power plant, Manisa-Turkey. – Energy Sources,

112. Kolev, T., R. Bakalska, B. Shivachev, R. Petrova. Codeinone. Acta Cryst. E,

113. Mihailova, B., M. Gospodinov, U. Bismayer, B. Gьttler, L. Konstantinov, M. Aroyo. 2005. Nanoscale phase transformations in relaxor-ferroelectric PbSc0.5(Nb,Ta)0.5O3 . A Raman spectroscopic study. – Bulgarian Journal of Physics, 32,

114. Penev, V., L. Konstantinov, M. Marinov. Geometrization of the language of chemistry: Approximate spatial mathematical model of different species of atoms and Mendeleev's Periodic Law. – Academic Open Internet Journal,

115. Penev, V., N. Zidarov, B. Zidarova. Geometrization of the language of mineralogy: Review of the basic results. ZVMO, (in Russian, with English Abstracts)

116. Shivachev, B., R. Petrova, M. Marinov, N. Stoyanov, A. Ahmedova, M. Miteva. Four cycloalkanespiro-5'-hydantoindithiones. Acta Cryst.,

117. Stoyanova M., S. Angelova, K. Kossev, V. Enchev, M. Palamareva. Ab-initio and DFT calculation of 4-[(pyrrolidine-1-yl)-carbonyl]-3-furyl-2-phenetyl-1,2,3,4-tetrahydroisoquinolin-1-one. – Tetrahedron Letters.

118. Zidarov, N., E. Tarassova, I. Peytcheva, A. v .Quadt, V. Andreichev, R. Titorenkova. Skrut granodiorite – manifestation of Lower Triassic magmatism in Belassitsa Mountains, SW Bulgaria. – Geologica balcanica,


REPORTS ON SCIENTIFIC EVENTS:

119. Bakardjieva, S., L. Szatmary, V. Stengl, J. Subrt, J. Lukas, N. Petrova. 2005. Brookite TiO2-correlation between morphology and photoactivity. – International Symposium Catalytic processes on advanced micro- and mesoporous materials, Abstracts, September 2-5, 2005, Nessebar, Bulgaria, p. 123.

120. Buosi, L., L. Martins, L. Dimitrov, M. Wallau, E. A. Urquieta-Gonzбlez. 2005. Уxidos metбlicos (Cu, Co, Fe)/HZSM-5 para a reduзгo seletiva de NO a N2 com propane. – 13o Congresso Brasileiro de catбlise, Foz de Iguacu, Setembro 10-15.

121. Campos, A. A., C. R. Silva, M. Wallau, L. Dimitrov, E. A. Urquieta-Gonzбlez. 2005. Recrystallisation of SBA-15 into ZSM-5/SBA-15 composites. Third International FEZA conference, August 23-26, Prague, Czech Republic.

122. Ganev, V. Y, D. D. Nihtianova, I. P. Mincov, U. Kolb. 2005. Structural investigation of thermally treated Fe78Si9B13 metallic glass. – 7th National workshop Nano 2005, Abstracts, November 24-25, Sofia, p. 71.

123. Dimitrov, L., M. Wallau, E. A. Urquieta-Gonzбlez. 2005. Mesostructuration of mordenite zeolite nanoparticles. Seventh European Congress on Catalysis, August 28-September 3, Sofia.

124. Dimova, M., V. M. Dekov, G. M. Molin, C. Griggio, I. Rajta, I. Uzonyi. 2004. Cosmic spherules from metalliferous sediments of two spreading centers: EPR and MAR. 32th International Geological Congress, August 20-28, Florence, Italy.

125. Driesner, T., B. Kostova, C. A. Heinrich. 2005. Hydrodynamic and thermodynamic modelling of the formation of the Yuzhna Petrovitsa hydrothermal Pb-Zn ore deposit, Madan, Bulgaria. – Goldschmidt conference, Moscow, Idaho, USA, p. A 157.

126. Gonзalves, M. L., L. Dimitrov, M. Wallau, E. A. Urquieta-Gonzбlez. 2005. Sуlidos micro-mesoporosos preparados por mesoestruturaзгo de sementes de zeуlitas ZSM-5. – 13o Congresso Brasileiro de catбlise, Foz de Iguacu, Setembro 10-15.

127. Kaisheva, D., D. Doshkova, B. Mihailova. 2005. A possibility for studying relaxation processes in ferroelectric crystals. "Natural sciences 2005", Organized by the "K. Preslavski" University of Shumen, October 30 - November 3, Varna. (in Bulgarian)

128. Kalvachev, Y. 2005. Gold based catalysts in environmental important reactions. – Workshop „Immobilized organic compounds characterization and applications", Jun 3-6, Kiten, Bulgaria (in Bulgarian).

129. Kalvachev, Y. , V. Kostov-Kytin, S. Todorova, G. Kadinov. 2005. Synthesis of layered kenyaite in Zr-containing medium and its application for oxidation of hydrocarbons. – International symposium catalytic processes on advanced micro- and mesoporous materials, Abstracts, September 2-5, 2005, Nessebar, Bulgaria, p. 66.

130. Kalvachev, Y. , V. Kostov-Kytin, S. Todorova, K. Tenchev, G. Kadinov. 2005. Synthesis of kenyaite and its application for oxidation of hydrocarbons. – 7th National workshop Nano 2005, Abstracts, November 24-25, Sofia, p. 27-28.

131. Karolinny, R., C. de Lima. L. Dimitrov, M. S. Batista, E. A. Urquieta-Gonzбlez. 2005. Catalisadores do tipo perovskita para reduзгo de NO com CO. – 13o Congresso Brasileiro de catбlise, Foz de Iguacu, Setembro 10-15.

132. Konstantinov, L. 2005. Physical studies in CLMC. Annual issue, concerning the Year of Physics, April 2005. (in Bulgarian)

133. Kostadinova, D., N. Petrova, C. Gerardin, D. Tichit, I. Dragieva. 2005. Deposition-precipitation by borohydride reduction of metal nanoparticles on hydrotalcite support. – 7th National workshop Nano 2005, Abstracts, November 24-25, Sofia, p. 66.

134. Kostov-Kytin, V., B. Mihailova, Y. Kalvachev. 2005. Structural species in sodium titanosilicate precursor powders. – International symposium catalytic processes on advanced micro- and mesoporous materials, Abstracts, September 2-5, 2005, Nessebar, Bulgaria, p. 45.

135. Kostov-Kytin, V., Y. Kalvachev. 2005. Hydrothermal synthesis and characterization of novel sodium zirconosilicates. – International symposium catalytic processes on advanced micro- and mesoporous materials, Abstracts, September 2-5, 2005, Nessebar, Bulgaria, p. 68.

136. Mihailova, B. 2005. Application of Raman spectroscopy in structural characterization of functional materials. – Invited lecture at the Summer seminar of the Graduiertenkolleg 611, Universitдt Hamburg, Hamburg, Germany, July 2005.

137. Mihailova, B. 2005. Nanoscale structural transformations in relaxor ferroelectrics. – Invited talk at the Winter colloquium 2005/2006, Institut fьr Geowissenschaften, Universitдt Tьbingen, December 2005.

138. Mihailova, B.,M. Gospodinov, U. Bismayer, B. Gьttler, L. Konstantinov, M. Aroyo. 2005. Nanoscale phase transformations in relaxor-ferroelectric PbSc0.5(Nb,Ta)0.5O3 . A Raman spectroscopic study. – International conference "Advances in Physics and Astrophysics of the 21st Century", September 611, Varna, Bulgaria.

139. Peytcheva, I., A. v. Quadt, M. Frank, N. Georgiev, Zh. Ivanov, C. A. Heinrich. 2005. How gabbro zircons contain more U than zircons from the co-mingled granodiorite: Lessons from U-Pb and Hf-zircon isotope investigations. Earth Palnet. Sci Letters, Abstracts , v. 15, V.M. Goldschmidt Conference, May 2005, Moscow, Idaho, p. 155

140. Stanimirova, Ts., N. Petrova, S. Bakardjieva, G. Kirov. 2005. Microscopic investigation of Mg-Al oxides from hydrotalcite. – International symposium catalytic processes on advanced micro- and mesoporous materials, Abstracts, September 2-5, 2005, Nessebar, Bulgaria, p. 76.

141. Vitov, O. 2005. Mineral diversity of stream sediments samples from Kjustendil region. – III International symposium "Mineral Diversity – research and preservation", Abstracts, October 7-10, 2005, Earth and Man National Museum, Sofia, 23-24.

142. Vitov, O., I. Marinova. 2005. Mineral diversity and cinnabar in stream sediments samples from Bulgaria. – III International symposium "Mineral Diversity - research and preservation", Abstractss, October 7-10, 2005, Earth and Man National Museum, Sofia, 20-22.

143. Von Quadt, A., I. Peytcheva, V. Bolz, C. A. Heinrich. 2005. Cretaceous magmatism and Cu-Au mineralization in the region of Apuseni-Banat-Timok-Srednogorie belt – constrains from U-Pb zircon and Re-Os molibdenite dating. – Earth Palnet. Sci Letters, Abstracts, v. 15, V.M. Goldschmidt Conference, May 2005, Moscow, Idaho, p. 568.

144. Yoleva, A., P. Djambazov, S. Djambazov, O. Petrov. 2005. Structural changes in opal from Stambolovo deposit (Bulgaria) after thermal treatment. – XV Scientific conference on Glass and Ceramics, September 2005, Varna.

145. Wallau, M., L. Dimitrov, E. A. Urquieta-Gonzбlez. 2005. Silicalita-1 mesoporosa preparada por nano-moldagem seqьencial. 13o Congresso Brasileiro de catбlise, Foz de Iguacu, Setembro 10-15.

146. Zidarov, N., D. Stojanov , Y. Tzvetanova. 2005. Agates from Eastern Rhodopes (Bulgaria) a specialized scientific collection of CLMC "Acad. Ivan Kostov", BAS. – III International symposium "Mineral Diversity – research and preservation", Abstracts, October 7-10, 2005, Earth and Man National Museum, Sofia, 32-33. (in Russian)