Geochemical characteristics of mercurian tetrahedrite , barite and fl uorite from the Duboki Vagan , Glumac and Dubrave-Dugi Dol barite deposits , south of Kreševo , Mid-Bosnian Schist Mts .

The geochemical characteristics of tetrahedrite and barite of the Duboki Vagan barite deposit near the town of Kreševo in the MBSM (Mid-Bosnian Schist Mountains) have been determinated and correlated with the results of previously studied barite, from the adjacent Glumac deposit, and fl uorite, from the Dubrave-Dugi Dol barite deposits. The studied tetrahedrite is characterized by a high content of Au (39 ppm) and Ag (>300 ppm), the presence of Co (63.5 ppm), Ni (266.2 ppm) and Cd (313,6 ppm) in the crystal lattice and negative δSCDT values (–11.80‰). On the plot of its C1 chondrite-normalized REE abundances, a slightly expressed positive Eu anomaly and high HREE concentrations are observed. The high content of SrSO4 (2.33 to 3.42 wt.%) in the barite crystal lattice indicates hydrothermal parent solutions. The δSCDT values of the studied barite are +10.40‰, which is typical for Permian seawater and its δOSMOW values range between 15.6 and 17.7‰. A distinct positive Eu anomaly is shown on the plot of the C1 chondrite-normalized REE abundances in barite. Geochemical characteristics of the studied tetrahedrite and barite of Duboki Vagan are very similar to those of previously investigated Glumac and Dubrave-Dugi Dol barite deposits. The fl uorite from the Dubrave-Dugi Dol deposits displays a negative Eu anomaly and its Tb/La and Tb/Ca ratios indicate a quite different origin in relation to barite formation. This is all in the accordance with the possible existence of two different paragenetic types of barite deposits in the MBSM and SEB (Southeastern Bosnia), which signifi cantly differ in the δOSMOW ranges of their barites and δSCDT values of their sulphides. The fi rst type of barite deposits originated in the Late Variscan phase (Lower Permian). It is characterized by numerous Cu, Fe, Zn, Sb, As, Pb sulphides and Cu-Sb-tetrahedrite without mercury, all having positive δSCDT values (0 to +5 ‰). Early intercontinental rifting took place between the uppermost Permian and Lower Triassic and enabled, in a great number of ba rite deposits, (especially in the MBSM), remobilization and partial fl uidization of their Fe, Cu, Zn, Sb and Pb sulphides which reacted with ascended mercury, sulphur and fl uorine rich mantle fl uids and resulted in the formation of Hgtetrahedrite and octahedral fl uorite. These processes caused the occurrence of the second paragenetic type of barite deposit with Hg-tetrahedrite as the main ore mineral, but characterized by strongly negative δSCDT values.


INTRODUCTION
In the Mid-Bosnian Schist Mountains (MBSM) and Southeastern Bosnia (SEB) two completely different paragenetic types of barite deposits occur.Small amounts (<10%) of diverse sulphides (pyrite, chalcopyrite, sphalerite, galena, arsenopyrite and tetrahedrite without mercur) occur with barite in the fi rst type.The second type of barite deposit is almost monosulphidic containing only Hg-tetrahedrite.There is a remarkable geochemical difference between the sulphides of these two types of barite deposits.All sulphides of the fi rst type are characterized by positive δ 34 S CDT values (0 to +5‰), whereas the Hg-tetrahedrite of the second type contains negative δ 34 S CDT values (-4.95 to -15.40‰).Additionally, JURKOVIĆ et al. (2010), found that the δ 18 O SMOW values in barite of the fi rst polysulphide type are signifi cantly lower (+14.2‰ to +15.6‰) than the δ 18 O SMOW values in barite from the second monosulphidic Hg-tetrahedrite type (+15.8‰ to +22.4‰).Such differences can be explained by lower temperature and lower salinity of mineralisation in the fi rst type of barite deposits JURKOVIĆ et al. (2010).These authors state that the fi rst polysulphide paragenetic type of barite deposits originated in Late Variscan phase (Lower Permian).The second one originated in Post Variscan/Early Eoalpine phase due to the exposure of the fi rst barite deposit type to the impact of early intercontinental rifting (JUR KO-VIĆ et al., 2010).
The aim of this work is to investigate the geochemical characteristics of the tetrahedrite and barite of the Duboki Vagan barite deposit near Kreševo in the MBSM, correlate them with the results of previously studied barite from the adjacent Glumac deposit and fl uorite from the Dubrave-Dugi Dol barite deposits.In addition a broad comparison of these results with geochemical characteristics of the other barite deposits in the MBSM and SEB will be made.

Geology
The Duboki Vagan, Glumac and Dubrave-Dugi Dol barite deposits occur in the area which surrounds the town of Kreše vo and belongs to the Mid-Bosnian Schist Mountains (MBSM).According to JOVANOVIĆ et al. (1977JOVANOVIĆ et al. ( , 1978)), rocks of Palaeozoic and Triassic age have been recognized in this area.The lowermost part of the Palaeozoic sequences includes chlorite and muscovite schists, phyllites and argillaceous schists, quartzites and lidites.The overlying dolomites, dolomitic limestones and marbles are found to be Devonian in age (SOFILJ et al., 1980).Magmatic rocks occur as porphyrites forming sills within chlorite and muscovite schists, and as quartz porphyry and keratophyre extrusions being situated on the verge of the Devonian carbonate complex (JURKOVIĆ, 1987).The youngest Palaeozoic sediments consist of conglomerates, sandstones, phyllites with Permian fl ora and brecciated limestones (JURKOVIĆ, 1987).The Lower Triassic is represented by sandstones, clay-like schists, marls and rare limestones, while the Middle Triassic is composed of dolomites and limestones.The lower Ladinian horizons consist of sandstones, hornstones, marls, claylike schists and rare limestones, whereas limestones dominate in upper Ladinian horizons (JURKOVIĆ, 1987).The geological relationships between the Lower Palaeozoic metamorphic complex and the overlying (<300 m thick) carbonate complex are not clear.The occurrence of barite deposits is exclusively related to the Upper Silurian -Devonian metaclastites and dolomites (Fig. 1).

Duboki Vagan
The northern border of the Duboki Vagan ore deposit runs 1 km south of the town of Kreševo and its southern limit is 4 km south of Kreševo (Fig. 1).The Duboki Vagan lies at absolute altitudes of +800 to +1000 m.Barite is the main ore mineral (50−75% of the ore mass), while pyrite and Hg-tetrahedrite (2-3%) are subordinate ore minerals.Quartz is the main gangue mineral (25-33% of the ore mass), followed by subordinate siderite (which is strongly oxidized into goethite).Octahedral fl uorite is an accessory mineral.The deposit is hosted by the Devonian dolomite, intruded by a large mass of metarhyolite (1-2 km 2 ) which crystallized from an S-type granitoid magma (JURKOVIĆ et al., 2010).
The Duboki Vagan deposit lies in a large, 20 m deep karstifi ed depression.The bottom of the depression is fi lled with rubble and blocks of siliceous barite which represented gangue from an earlier time.Part of this material comes from mining operations, but part is the residue left by the weathering and leaching out of the ore-bearing Devonian dolomite.The ancient miners removed only cinnabar, which was necessary for the amalgamation of gold from Hg-tetrahedrite, and limonite used in the production of iron.
In recent times the old dumps and elluvial deposits have been worked over and barite recovered.This clearing up has afforded a better view of the morphology of the Duboki Vagan barite deposit.The ore bodies are irregular seams running NW-SE, 1-1.5 m thick, dipping towards the NE, but there are also satellite barite veins.Recently, MIKO performed a quantitative chemical analysis of one Hg-tetrahedrite sample from the Duboki Vagan deposit (JURKOVIĆ & MIKO, 1997)

Glumac
The Glumac barite deposits are situated at elevations of 800 to 920 metres above sea level on the northern side of Me đuvršje mountain and ~1 km south of Kreševo.Ore bodies occur in different forms (nests, veins, irregular bodies, ore breccias), and are usually very irregular (JURKOVIĆ, 1987).The main mineral is barite, whereas calcite, ankerite, fl uorite, neodolomite, Hg-tetrahedrite, pyrite and quartz are subordinate (JURKOVIĆ, 1987)
Examination of the waste heaps and elluvial material has revealed that barite is the main mineral, with signifi cant quantities of quartz, lesser amounts of pyrite, signifi cantly less Hg-tetrahedrite (exploited by Roman and medieval miners), and a considerable quantity of Au-Ag-bearing limonite.KATZER (1907) determined the approximate relationship of the main minerals: 40.2% barite, 32.6% quartz, 2.4% tetrahedrite, 0.8% Cu and 24.8% soluble matter what is equal 100.8% in total.JURKOVIĆ et al. (1997) presented the fi rst geochemical data of barite and tetrahedrite from the Duboki Vagan barite deposit (see Tables 1 and 3).

ANALYTICAL METHODS
The quantitative chemical analysis of Hg-tetrahedrite (D-VAGT sample) was performed by Acme Analytical Laboratories, Vancouver Ltd., Canada (Table 1).The trace element content of Hg-tetrahedrite (D-VAGT sample) and barites (VAG and DUV samples) was analysed by inductively coupled plasma (ICP) mass spectrometry in the same laboratory (Tables 2 and 3).
The isotope composition of sulphur in the Hg-tetrahedrite (D-VAGT), oxygen in barite (VAG) and sulphur and oxygen in barite (DUV) were determined in the Stable Isotope Laboratory of the University of Laussane, Swiss, using a Finnigan Mat Facility (Table 4).The chemical composition of Hg-tetrahedrite from the Duboki Vagan barite deposit was determined by Slobodan MIKO (in JURKOVIĆ & MIKO, 1997) by atomic absorption spectrometry (AAS) and by ICF-AES after Br-HCl digestion (Table 1).
Two clear fl uorite crystals from the Dubrave-Dugi Dol barite deposits were analysed 15 years ago by INAA (Instrumental Neutron Activation Analysis) in the Institute for Petrology and Geochemistry, Karlsruhe University, Germany (PALINKAŠ & JURKOVIĆ, 1994).

Hg-tetrahedrite
The analysed Hg-tetrahedrite (sample D-VAGT) from Duboki Vagan was very fi ne-grained, densely dispersed in the gangue consisting of barite, quartz and calcite.Tetrahedrite grains were carefully handpicked under a binocular microscope.The chemical analysis revealed that it is a mercurybearing Cu-Sb-Zn tetrahedrite, strongly weathered, containing ~ 2.73 wt.% of mechanically admixed barite, (which has 3.425 wt.% SrSO 4 built into its crystal lattice), calcite and galena (Table 1). Co (63.5 ppm), Ni (266.2 ppm) and Cd (313.6 ppm) were detected in the crystal lattice of the tetrahedrite for the fi rst time in the MBSM (Table 1).These elements, together with Bi, W, Sn and Se, are constituent elements in the tetrahedrite crystal lattice (DUDA et al., 1987).Their concentrations so far in analysed barite samples, (7 from the MBSM and 6 from the SEB), were mostly below minimal detection limits (MDL) and only rarely around MDL.This suggests that the presence of admixed barite in the analysed sample could only inconsiderably infl uence the abundance and distribution of trace elements in the Hg-tetrahedrite.
Very high values of Au (39 ppm) and Ag (>300 ppm) were found in this tetrahedrite (Table 1).
Standard trace element analysis including 22 elements shows the presence of only 10 elements (Rb, Ta, U, Zr, Y, Mo, Pb, Bi, Sr and Ba) in tetrahedrite, while 12 of them (Be, Sc, Cs, Ga, Hf, Nb, Sn, Th, V, W, Tl and Se) were below MDL (Table 2).
The total sum of the rare earth elements (REE) in the studied tetrahedrite is only 15.03 ppm although all 14 REE were analysed (Table 3).La shows by far the highest concentration (10.6 ppm) and the ratios of La N /Yb N (27.11) and ΣLREE / ΣHREE (5.530) indicate enrichment of the total LREE against the total HREE.But, excluding La, the LREE N are depleted with regard to the HREE N as clearly shown in the plot of REE normalized to CI chondrite values (SUN & McDONOUGH, 1989) presented in Fig. 2. The REE pattern is characterized by a pronounced positive Eu anomaly (Eu/ Eu* = 2.48) and expressed as a negative Ce anomaly (Ce/ Ce* = 0.220).

Barite
Table 2 presents the values of 30 analysed trace elements of both barite samples (VAG and DUV) taken from the Duboki Vagan barite deposit.
The group of elements between Be and Y consist of 17 elements but only Ni, Hf, Ta, W and Y were detected in both barite samples.Additionally, Ga, U and Zr were also found in the VAG sample.The values of 8 other trace elements of this group (Be, Co, Sc, Cs, Nb, Sn, Th and V) were below the MDL.The total content of the Be-Y trace element group is very low in both barite samples (<24.8 ppm in the VAG sample and <16.2 ppm in the DUV sample).
In the second group of 13 trace elements between Mo and Se only 5, (Cu, Zn, As, Sb and Hg) were detected in analyses of both barite samples.Pb and Tl were only found in the VAG sample, while Au (0.9 ppb) is present only in the DUV sample.There were 5 trace elements (Mo, Cd, Bi, Ag and Se) below the MDL.The total sum of the trace elements of the Mo-Se group in the VAG sample is <102.41ppm where As (87.8 ppm) dominates.In the DUV sample the total sum of the same elements is <84.58 ppm, but here Cu (66.0 ppm) dominates.The analysed REE in barite are characterized by extremely low values: 7.77 ppm in total in the VAG sample and 7.98 ppm in total in the DUV sample (Table 3).The La N /Yb N ratio in the VAG sample corresponds to 7.18, and the ΣLREE / ΣHREE ratio is 0.63, whereas in the DUV sample the same ratios are 47.03 and 1.58 respectively.The values for Nd and Sm in both samples, and also the value of Dy in the DUV sample, were below the MDL.Therefore the values of the Eu anomaly (Eu/Eu*) could not be calculated.However, it is obvious from the plot of the REE pattern normalized to CI chondrite (SUN & McDONOUGH, 1989) that both samples have pronounced positive Eu anomalies because of the extremely low concentration of Sm (Fig. 3).The expressed negative Ce/Ce* anomaly is visible in both samples (where Ce/Ce* = 0.220 in the VAG sample and 0.440 in the DUV sample).
The wt.% of SrSO 4 in barite varies in the VAG sample from 2.51 to 3.42 (thin fi ne grained and thick tabular coarse grained habits of barite crystals of the same sample) and in DUV sample equates to 2.33 (Table 4).
The δ 34 S CDT value of barite (DUV sample) is +10.4‰, while the δ 18 O SMOW values of barite in the VAG and DUV samples are +15.6 and +17.3‰ respectively (Table 4).

DISCUSSION
In this section, these results will be compared with those from previously published papers concerning fl uid inclusion
Very high values for gold and silver were determined in the studied Hg-tetrahedrite, where 39 ppm Au and >300 ppm Ag is a typical, genetically very important characteristic of all MBSM Hg-tetrahedrites (JURKOVIĆ et al., 1997;JURKOVIĆ et al., 2010).In a tetrahedrite sample from the Duboki Vagan deposit analysed earlier (JURKOVIĆ et al., 1997), 1290 ppm Ag was obtained (Table 1).Comparing the analyses of both Duboki Vagan tetrahedrite samples, (the fi rst analysed in 1997 and the second from the present study), it is obvious that they are very similar in Cu, Fe, Zn and As values.The analysis performed here demonstrates that Sb, Hg and S are the most rapid weathering components of Hgtetrahedrite (Table 1).

Sample
In general, negative Ce anomalies are characterized by oxidizing conditions.A negative Ce anomaly appears to be a function of O 2 and pH, but is more sensitive to pH than to O 2 .In natural aqueous systems, the occurrences of Ce anomalies are due to the redox reaction: 2Ce 3+ + 0.5O 2 + 3H 2 O = 2CeO 2 + 6H + (BAU & MÖLLER, 1992).The generation of Ce anomalies in a high-temperature environment seems unlikely, because with increasing temperature, the Ce 4+ /Ce 3+ redox equilibrium shifts toward higher fO 2 .According to WOOD (1990WOOD ( , 1990a)), with increasing temperature both the Ce 4+ /Ce 3+ ratio and the Ce complex formation constants increase.
So far, only one REE analysis was performed on the MBSM barites, which was the analysis of the K-GLU sample from the Glumac barite (JURKOVIĆ et al., 2010).The two new REE analyses performed here on the Duboki Vagan barite samples (VAG and DUV) produced almost identical results, despite the fact that there are small differences in mineral paragenesis.
It has to be stressed that the δ 34 S CDT value obtained from the analyzed barite (+10.40‰)corresponds well with earlier published data of δ 34 S CDT values in barite (+10.11‰ on average) and is typical for Permian seawater (Table 4).

Fluorite
In order to compare the REE distribution pattern in barite and tetrahedrite analysed here with those in fl uorite published by PALINKAŠ & JURKOVIĆ (1994) in the Dubrave-Dugi Dol barite deposits, the plot of REE distribution in fl uorite normalized to CI chondrite is shown in Fig. 4.
The fl uorite crystals (DD-FA and DD-FB) studied by PALINKAŠ & JURKOVIĆ (1994), show extremely low REE values of 0.427 and 0.406 ppm respectively.Such fl uorites, with a total REE content of about only half that of chondrites, were reported by MÖLLER & MORTEANI (1983) and EPPINGER & CLOOS (1990) from limestones in the Alps, Spain, Morrocco and the USA.MÖLLER & MORTE-ANI (1983) maintain that these fl uorites have been formed under hypersaline conditions or in evaporating basins.SCH-NEIDER et al. (1975), investigating fl uorite in the Northern Calcareous Alps, also reported extremely low total REE values of 0.17, 0.57 and 0.72 ppm.
The formation of barite and fl uorite took place under opposing environmental conditions.The Ce anomalies, although less pronounced, are also of opposite character.SCHNEIDER et al. (1975, 1977), and MÖLLER et al. (1976), distinguish fl uorite of hydrothermal and sedimentary origin, on the basis of the Tb/Ca atom ratio and the Tb N /La N ratios.Tb N /La N -Tb/Ca ratios for the fl uorites from the Dubrave-Dugi Dol barite deposits (PALINKAŠ & JURKOVIĆ, 1994), plot into the "sedimentary fi eld" according to SCH-NEIDER et al. (1975, 1977).In contrast, barites, as evidenced by their 87 Sr/ 86 Sr ratios are of hydrothermal origin.These data support the idea that barite on the one hand, and Hg-tetrahedrite (±octahedral fl uorite) on the other, have been formed at different times and in dissimilar environments.A Tb/La ratio >1.0 indicates late stage formation from a mineralization solution.The enrichment of the MREE and HREE relative to the LREE may have been due to the formation of their stable F -and CO 3 2-complexes.

Origin of barite deposits in the MBSM and SEB
According to JURKOVIĆ et al. (2010), two paragenetic types of barite deposits have been formed in the MBSM and SEB during two mineralization phases.
The fi rst, (older) phase, took place during the early Permian (Cisuralian), and produced veiny and metasomatic bar- ite deposits with subordinate or scarce Fe, Cu, Zn, Pb and Sb sulphides and sulphosalts.These had positive δ 34 S CDT values (±0 to +5‰), with some siderite and quartz as gangue minerals.This paragenetic type of barite deposits formed throughout the MBSM and also in the Prača-Foča region of the SEB, and in the Jajce-Jezero region (the outermost NNW part of the MBSM).The best example of this type of barite deposit is the thoroughly studied Trošnik ore deposit near Fojnica (MBSM), which formed as irregular metasomatic bodies and veins within the Lower Palaeozoic dolomite (JURKOVIĆ, 1958;JURKOVIĆ et al., 1997).Quartz, siderite and barite are the main gangue minerals.Pyrite and chalcopyrite are the main ore minerals, whereas tetrahedrite is subordinate.All sulphides are characterized by positive δ 34 S CDT values.Three tetrahedrite samples from the Trošnik ore deposit produced +3.24‰ and +3.73‰ (KUBAT et al., 1979/80) and+4.00‰ values (JURKOVIĆ et al., 2010).Tetrahedrite from the Trošnik deposit contains only traces of mercury (<0.20% and 0.03% according to JURKOVIĆ et al., 1997), and is formed by hydrothermal fl uid from the same sulphur source, as for pyrite and chalcopyrite in the same paragenesis.This fact indicates that the Trošnik ore deposit has suffered a negligible overprint during a later phase.
The second (younger) mineralization phase took place at the end of the Permian (Permian-Triassic boundary), when Early Intracontinental Rifting started.This period was characterized by heating, dilatation and fracturing of the greater part of the MBSM, enabling the rise of mercury, fl uorine and H 2 S from the upper mantle.KARAMATA et al. (1995), published the highest concentration of mercury in the Dinarides which occurred in the Lower and Middle Triassic.The sulphides and sulphosalts formed during the fi rst mineralization phase were regenerated, remobilized, partly and/or completely fl uidized and reacted with ascending mercury and sulphur from the new source.These processes led to formation of the only Hg-tetrahedrite characterized by negative δ 34 S CDT values, ranging between -4.95‰ and -15.4‰ and also of high-temperature octahedral fl uorite.The rifting overprint (impact metasomatism) occurred very irregularly and with very differing intensity in various parts of the MBSM, SEB and Jajce-Jezero areas.The most strongly affected areas were probably fault zones of the fi rst and second order, and zones warmed by magmatic eruptions.The most intensive processes and overprinting took place in the Rostovo, Gornji Vakuf and Kreševo areas, whereas a very weak overprint occurred in SE Bosnia.
Barite formed during the fi rst mineralization phase underwent strong heating and a change of pressure and f(O 2 ) in the environment during the later second phase.These events are refl ected in the shift of δ 18 O SMOW values toward higher values, and δ 34 S CDT values toward lower values in barite (JURKOVIĆ et al., 2010).Sulphide-bearing barites from SEB which are weakly overprinted, and have δ 18 O SMOW values within a narrow range (+14.6‰ to +15.6‰), whereas barite samples with Hg-tetrahedrite and fl uorite from the MBSM, reveal higher δ 18 O SMOW values ranging from +15.6 to +22.4‰.The sulphur isotopes (δ 34 S CDT ) in the barites from the SEB span a range from +11.6 to +17.7‰ (mean +16.4‰).
Barites from the MBSM also display a narrow range of δ 34 S CDT values between +10.1‰ to +16.8‰, but with a signifi cantly lower mean value of +11.8‰ (JURKOVIĆ et al., 2010).The most pronounced result is a very expressive positive Eu anomaly in all the overprinted barite samples, which suggests a high-temperature mineralizing fl uid.

CONCLUSION
A broad comparison of geochemical data was undertaken of barite deposits associated with subordinate or scarce Fe, Cu, Zn, As and Sb sulphides and sulphosalts, characterized by a positive δ 34 S CDT value (±0 to +5‰) with barite deposits where Hg-tetrahedrite, as the only sulphide mineral, was characterized by negative δ 34 S CDT values (-4.95 to -15.4‰) and which is locally associated with high-temperature octahedral fl uorite.
The following facts and data were established as a result: 1) Both paragenetic barite types are contemporaneous and have an epigenetic hydrothermal origin.They also share almost the same 87 Sr/ 86 Sr ratio, (the difference is only 0.0041), and very similar REE contents (on average 7.1 and 8.3 ppm respectively).The most pronounced difference between the two paragenetic types is observed in the oxygen isotopic com position of the barites.Polysulphide-bearing barites show a δ 18 O SMOW value within a narrow range (+14.6‰ to +15.6‰), whereas Hg-tetrahedrite bearing barites have δ 18 O SMOW values ranging from +15.6 to +22.4‰.Differences in the sulphur isotope composition have also been noted, but are inexplicable.
2) A new sulphur source was vital for formation of the Hg-tetrahedrite (schwazite).Most probably, it was H 2 S that ascended from the upper mantle during early intercontinental rifting and/or organic sulphur being formed in the ores and rocks of completely different sedimentary environments.
3) The octahedral, high temperature fl uorite occurs only in the Hg-tetrahedrite-bearing barite deposits.It is characterized by extremely low REE contents, a low La N /Yb N ratio indicating a very distinct enrichment of HREE and late stage formation of fl uorite.4) A very low REE (0.4 to 0.45 ppm) content indicates the formation of fl uorite under hypersaline conditions or in evaporating basin.Increased values for Sm and decreased values for Tm in the Sm N /Tm N ratios, characterize fl uids supersaturated with respect to CO 2 and halides.5) Tb N /La N -Tb/Ca atom ratios of fl uorites from the Dubrave-Dugi Dol barite deposits plot in the sedimentary fi eld of SCHNEIDER et al. (1975SCHNEIDER et al. ( , 1977)), while all barites have a hydrothermal origin.This indicates great differences in the timing and environmental circumstances of barite and fl uorite formation.6) All the described events are effects of the early intercontinental rifting which took place between the uppermost Permian and Lower Triassic.Concerning the strength and intensity of this geological event, it affected separate parts of the MBSM and SEB in very different ways.The most important event was the ascension of mercury, fl uorine, boron and sulphur from the upper mantle, and very strong heating and tectonization.These circumstances enabled remobilization and partial fl uidization of primary Fe, Cu, Zn, Sb and Pb sulphides and their reaction with the ascended mercury and sulphur, followed by formation of octahedral fl uorite, tourmalinization and large, local masses of calcite.In a single case (Fočanska Jabuka) a new barite body was formed in this younger phase containing one even younger Hg-tetrahedrite vein, characterized by a strongly negative δ 34 S CDT value -4.95‰.
7) The Duboki Vagan barite deposit, together with in this work compared the Glumac and Dubrave-Dugi Dol barite deposits originated in the Late Variscan (Lower Permian).Early intercontinental rifting in the Post Variscan (Early Eoalpine phase), triggered processes that caused the shift of barite δ 18 O SMOW values, remobilization and partial fl uidization of primary polysulphides and formation of Hg-tetrahedrite as the only ore mineral with octahedral fl uorite.

Table 2 :
JURKOVIĆ et al. (2010)of Hg-tetrahedrite (D-VAGT) and barite (VAG, DUV and K-GLU) from the barite deposits, south of Kreševo.D-VAGT, VAG and DUV samples are from the Duboki Vagan deposit, while K-GLU sample is from the Glumac deposit.Data for K-GLU sample are fromJURKOVIĆ et al. (2010).All values are in ppm, except those of Au, which are in ppb.