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Articles |
1 Natural History Museum, University of Oslo, Boks 1172 Blindern, N–0318 Oslo, Norway
2 South Australian Museum, North Terrace, Adelaide, S.A., 5000, Australia and Department of Earth and Environmental Sciences, University of Adelaide, S.A., 5005, Australia
3 Department of Mineralogy, The Natural History Museum, Cromwell Road, London SW7 5BD, U.K.
4 Institute of Mineralogy, University of Salzburg, Hellbrunnerstr. 34, A–5020 Salzburg, Austria
5 Department of Geology, University of Turku, FIN-20014 Turku, Finland
E-mail address: nigelc{at}nhm.uio.no
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ABSTRACT |
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 Top Abstract IntroductionThe Ocurrences We StudiedDescription of the SamplesMicro-analytical DataReflectance DataX-Ray-Diffraction DataDiscussionConclusionsAknowledgementsReferences |
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Keywords: tellurosulfides, aleksite, compositional data, unnamed phases, Clogau, Wales, Iilijärvi, Finland, Fragant, Austria.
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INTRODUCTION |
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TopAbstractIntroductionThe Ocurrences We StudiedDescription of the SamplesMicro-analytical DataReflectance DataX-Ray-Diffraction DataDiscussionConclusionsAknowledgementsReferences |
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The single other recognized Pb–Bi–Te–S mineral, saddlebackite, Pb2Bi2Te2S3, is known only from the type locality, the Boddington gold deposit, Western Australia (Clarke 1997) and from Kochkar, where it had been recognized as a possible new mineral two years earlier (Spiridonov 1995). In the description of saddlebackite as a new mineral, Clarke (1997) emphasized that the species was probably structurally related to aleksite and tetradymite.
In four of the aforementioned descriptions (Lipovetskiy et al. 1976, Bevins & Stanley 1990, Bonev & Neykov 1990, Clarke 1997), a further phase was reported, with the composition PbBi4Te4S3. This was termed "Phase C" in the first of the above descriptions, a descriptor we shall also use in this paper, in which we present new paragenetic and micro-analytical data for the aleksite–"phase C" assemblage from the Clogau mine, North Wales. We also describe the occurrence, the composition and the paragenesis of other unnamed Bi–Pb–Te–S compounds from the Iilijärvi deposit, southwest Finland, and from Fragant, Austria. These latter group of phases have compositions in the range Pb5Bi4Te4S7 – Pb7Bi4Te4S9, i.e., richer in both Pb and S than aleksite or saddlebackite.
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THE OCURRENCES WE STUDIED |
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TopAbstractIntroductionThe Ocurrences We StudiedDescription of the SamplesMicro-analytical DataReflectance DataX-Ray-Diffraction DataDiscussionConclusionsAknowledgementsReferences |
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The Clogau mine lies in the southern part of the Dolgellau gold belt on the southeastern margin of the Harlech Dome in North Wales, U.K. (Shepherd & Bottrell 1993). The vein systems are identified as pre-tectonic with respect to the early Devonian deformation (Mason et al. 1999, Platten & Dominy 1999), although Shepherd & Bottrell (1993) reported an age of 405 ± 6 Ma for the mineralization at Clogau. Quartz – sulfide – gold veins have been worked periodically since the 1850s, and a substantial body of data exists on their composition and conditions of formation (e.g., Bottrell & Spiro 1988, Bottrell et al. 1988, Shepherd et al. 1991). Bismuth- and tellurium-bearing minerals were described by Gilbey (1968) and later confirmed by Naden (1988), who stressed a correlation in timing between telluride and gold mineralization in the deposit. A first description of the aleksite-bearing assemblage from Clogau was given by Bevins & Stanley (1990). We have re-investigated specimen E.1309 (Natural History Museum, U.K.), in which aleksite and "phase C" occur together with galena and tellurobismuthite. One of us (C.J.S.), together with coworkers, began to investigate this sample in detail in the early 1990s, obtaining X-ray diffraction, electron-microprobe and optical reflectance documentation, some of which is reported in the present contribution.
Iilijärvi, Finland
Selenides and tellurides of bismuth are conspicuous trace components of base-metal – gold ores in the Orijärvi area, southwestern Finland. Our reinvestigation of specimens from Orijärvi (Ciobanu et al. 2002), including type-material laitakarite (Laitakari 1934, Vorma 1960), has also included material from the satellite deposit at Iilijärvi, 1.3 km northwest of Orijärvi (Mäkelä 1989). The ores are dominated by pyrite, chalcopyrite, sphalerite and galena, within a matrix of quartz, biotite, cordierite and gahnite, and are hosted by 1.9-Ga-old supracrustal rocks, deformed and metamorphosed during the Svecokarelian orogeny. The Orijärvi region is widely known for the pioneering research in metamorphic petrology by Eskola (1914, 1915, 1950) and for the occurrence of complex triple- and double-chain pyriboles (Schumacher & Czank 1987).
Selenium-bearing sulfosalts of bismuth were previously reported from Iilijärvi (Borgström 1915, Vaasjoki & Kaitaro 1951). Our studies have focused largely on material collected by Aarne Laitakari in the 1930s and deposited in the collection of Turku University; this material has been supplemented by specimens collected from outcrops at the mine site in 2002. In addition to the Se-bearing sulfosalt assemblage (gies-senite –cosalite), our re-investigations have revealed abundant symplectitic intergrowths of gold with rutile and a number of selenium- and tellurium-bearing phases hosted within the sulfosalt assemblage (Ciobanu et al. 2002). We have interpreted these assemblages, and the preserved textures among component minerals, in terms of synmetamorphic remobilization from the "main" Orijärvi ore, coupled with extensive desulfidation and subsequent limited sulfidation contemporaneous with retrograde recrystallization.
Fragant, Austria
Tellurides of bismuth (tetradymite, joséite-type phases and pilsenite) are common constituents in structurally controlled and late-Alpine gold-bearing mineralization ("Tauerngoldgang-type") in various districts of Salzburg and Carinthia provinces, Austria. The ores are dominated by pyrite, arsenopyrite, chalcopyrite, galena and sphalerite, and are associated with a very complex spectrum of Ag(Cu)–Pb–Bi–(Sb) sulfosalts (Putz et al. 2003). The host rocks are either metagranitic rocks of Variscan age (Central Gneiss) or (pre)-Permian to Mesozoic rocks of the cover sequences. Fragant ("Langenleiten") is a small silver–gold deposit located in the southernmost part of the Sonnblick mountain range (Carinthia Province, Austria), close to the boundary with polymetamorphic complexes south of the Tauern Window. The structurally controlled mineralization occurs in a major shear-zone on top of the Central Gneiss, where extremely deformed segments of the same gneiss and calcareous mica-schists host the ore. The ore assemblage is dominated by galena, pyrite and chalcopyrite, forming irregular (patchy) inclusions in a quartz vein, which reaches up to 1 m in thickness. The Bi–Pb tellurosulfides are present as small inclusions in galena and are variably associated with sulfosalts such as cosalite (dominant), lillianite, felbertalite (Topa et al. 2001) and aikinite. Native gold occurs as rare grains in galena. Hand specimens yielded up to 1 ppm Au and 678 ppm Ag. The deposit is of metamorphic origin and was formed during the retrograde stage of the Alpine regional metamorphism.
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DESCRIPTION OF THE SAMPLES |
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TopAbstractIntroductionThe Ocurrences We StudiedDescription of the SamplesMicro-analytical DataReflectance DataX-Ray-Diffraction DataDiscussionConclusionsAknowledgementsReferences |
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Specimen E.1309 contains pyrrhotite, chalcopyrite and galena as major sulfides, with a telluride assemblage consisting of tellurobismuthite, hessite and two Bi–Pb tellurosulfides (aleksite and "phase C"), as well as minor gold. In the Clogau specimen, lath-like grains composed of aleksite, "phase C", tellurobismuthite, minor tetradymite and galena, 100–1000 µm in size, occur throughout the chlorite – calcite – quartz matrix. Under oil immersion, all these minerals are generally seen to be intergrown with one another, in some cases as fine-grained symplectites (Figs. 1, 2). Although some patches of aleksite and "phase C" appear homogeneous, others display an intimate intergrowth as lamellar banding, and may also include galena, which may be a decomposition or exsolution product. Optically, "phase C" and aleksite are rather similar in appearance. Both are green-grey in color, especially against tellurobismuthite and galena, which appear pinkish white and grey, respectively, and display moderate bireflectance. Under oil immersion, the slightly higher reflectance of "phase C" is evident. A single grain of saddlebackite, not previously recognized in the Clogau assemblage, was identified, intergrown with aleksite.
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Specimens from Iilijärvi are dominated either by galena, pyrrhotite and sphalerite, with considerable variations in sulfide assemblage on the hand-specimen scale. Samples display a distinct Sb- and Te-rich signature, rather than a Se-dominant character as at Orijärvi. Minor sulfides include chalcopyrite, pyrite, marcasite, molybdenite, arsenopyrite and cobaltite. The Bi-sulfosalts giessenite, Cu2Pb26(Bi,Sb)20S57, and cosalite, Pb2Bi2(S,Se)5, occur within galena. Both sulfosalts display substitution of Bi by Sb; ~10 mol.% in the case of cosalite and in the range 15–30 mol.% for giessenite. The Bi–Te–Se–S phases are abundant minor minerals within the galena–sulfosalt assemblages. Hedleyite, Bi7Te3, joséite-B, Bi4Te2S, joséite-A, Bi4TeS2 and ikunolite, Bi4(S,Se)3, with intergrowths among pairs of these phases, are abundant.
Aleksite and the unnamed phases that we focus on in this paper (Pb5Bi4Te4S7 – Pb7Bi4Te4S9 range) occur as individual and composite lamellae within galena and the Bi-sulfosalts (Figs. 3, 4). The phases in the Iilijärvi specimens are grey with a slightly darker tint against joséite-A, joséite-B or hedleyite.
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The specimens investigated are dominated by galena embedded in a quartz matrix and accompanied by subordinate amounts of pyrite and chalcopyrite. Galena contains numerous inclusions of various sulfosalts, such as cosalite, Ag-poor members of the lillianite–gustavite homologous series, felbertalite and aikinite (Fig. 5a). All of them attain sizes up to several 100 µm. The Bi–Pb tellurosulfides, of which aleksite, PbBi2Te2S2, is the most abundant (Fig. 5a), are commonly intergrown with either cosalite or lillianite, rarely with felbertalite, but never with aikinite. They form lamellae up to 200 µm in length but only rarely exceed 20 µm in width.
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MICRO-ANALYTICAL DATA |
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TopAbstractIntroductionThe Ocurrences We StudiedDescription of the SamplesMicro-analytical DataReflectance DataX-Ray-Diffraction DataDiscussionConclusionsAknowledgementsReferences |
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Aleksite and "Phase C"
Compositional data for species in the range of aleksite and "phase C" from Clogau, Iilijärvi and Fragant are given in Tables 1 and 2. Plotted compositions (Fig. 6) show a relatively narrow, but nevertheless significant spread of Pb/(Pb + Bi) and Te/(Te + S) values across and beyond the ideal compositions of the two phases, with little evidence of an extensive compositional gap between the two. We note that a number of analytical datasets falling within this compositional gap were removed since they likely pertain to mixtures. The spread of the Pb/(Pb + Bi) and Te/(Te + S) values for aleksite from Fragant appears less extensive, although it will be noted that the dataset is smaller. Published data for "phase C" (Lipovetskiy et al. 1976, Bonev & Neykov 1990, Clarke 1997) are included in Table 2 for purposes of comparison.
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Only a single grain was identified in the Clogau specimen, with a composition close to Pb2Bi2Te2S3 (Table 1).
Pb-bearing tetradymite
We have analyzed tetradymite in the Clogau material and established contents of Pb that range from <1 wt.% up to as much as 8 wt.%, i.e., close to that of "phase C". We advise caution in the interpretation of these data, since we cannot be certain if this is Pb-bearing tetradymite or a submicroscopic mixture of tetradymite with Pb–Bi–Te–S phases.
Unnamed phases from Iilijärvi and Fragant
The two largest lamellae in the Iilijärvi samples were both analyzed with different electron microprobes. The largest lamella (grain 3; Fig. 3a), apparently homogeneous in back-scattered electron images, gives compositions in the range Pb6Bi4Te4S8 –Pb7Bi4Te4S9 (Table 3, Fig. 6), indicating inhomogeneity. The second lamella (grain 6, with a rim of hessite; Fig. 4b) has a somewhat different composition. Data points show variation in Pb/(Pb + Bi) and Te/(Te + S), but are clustered closer to Pb5Bi4Te4S7, with some individual compositions extending toward Pb6Bi4Te4S8. Analyses of the smaller lamellae and blebs in the specimens also gave a variety of compositions in the same general range. The total dataset, in which analyses yielding poor totals or charge balance and any points in which intergrowths were seen or suspected have been excluded, shows a range of (Pb + Bi)/(Te + S) values spread across a relatively broad compositional range between Pb5Bi4Te4S7 and Pb7Bi4Te4S9 (Fig. 6). For this reason, we choose not to distinguish distinct stoichiometries.
In the Fragant specimens, we have analyzed several lamellae either intergrown with aleksite or individually embedded in galena. All lamellae proved to be homogeneous. The chemical compositions obtained are close to Pb3Bi4Te4S5 (one analysis only), Pb5Bi4Te4S7 and Pb6Bi4Te4S8 (Table 4, Fig. 6).
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REFLECTANCE DATA |
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TopAbstractIntroductionThe Ocurrences We StudiedDescription of the SamplesMicro-analytical DataReflectance DataX-Ray-Diffraction DataDiscussionConclusionsAknowledgementsReferences |
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X-RAY-DIFFRACTION DATA |
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TopAbstractIntroductionThe Ocurrences We StudiedDescription of the SamplesMicro-analytical DataReflectance DataX-Ray-Diffraction DataDiscussionConclusionsAknowledgementsReferences |
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Liu & Chang (1994) conducted a series of synthesis studies on the system Pb–Bi–Te–S in which the synthetic equivalents of aleksite and saddlebackite, as compositional data for bi–pb tellurosulfides 427 well as "phase C", were obtained. Cell dimensions for these synthetic phases are compared with the data given above and other published unit-cell data for natural Bi–Pb tellurosulfides in Table 6. In the case of "phase C", agreement between unit-cell dimensions for the natural and synthetic phase seems excellent.
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DISCUSSION |
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TopAbstractIntroductionThe Ocurrences We StudiedDescription of the SamplesMicro-analytical DataReflectance DataX-Ray-Diffraction DataDiscussionConclusionsAknowledgementsReferences |
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An accretional homologous series?
A chemical dataset for Bi–Pb tellurosulfides should show either of the following aspects: (a) narrow ranges of chemical composition clustering around individual members of the series, surrounded by large compositional gaps. Such a scenario would sustain the idea of a series populated with discrete, stoichiometric phases; (b) continuous or semicontinuous variation in chemical composition across the series. The latter case can be explained either by more-or-less random submicroscopic intergrowths between stoichiometric members, submicroscopic mixtures between members of the series with galena or other minerals, or alternatively, complete solid-solution between two end-members.
The compositional data we have compiled do not comply with either explanation and therefore do not provide an answer as to whether there exists a definable series populated by discrete phases, or rather a continuous compositional range. We acknowledge that clustering around stoichiometric members is weaker than might be expected if the phases belong to an accretional homologous series with the general formula PbNBi4Te4SN+2. In such a hypothesis, in which N values are purely chemical and do not necessarily reflect homologous order, tetradymite, Bi4Te4S2, has N = 0, "phase C" has N = 1, aleksite, N = 2 and saddlebackite, N = 4, respectively. In this manner, the unnamed phases from Iilijärvi and Fragant would have N values between 5 and 7, and 5 and 6 (plus N = 3), respectively. The hypothetical extension of a series to such Pb-rich phases is, of course, highly speculative at this point, with no supporting structural data available at present.
The question of whether the discrete phases we have analyzed are real, and thus belong to a modular series, or whether there is continuous variation across the series, cannot be resolved without further work. Our data show a near-complete compositional range among Pb- and S-rich tellurosulfides (Pb5Bi4Te4S7 – Pb7Bi4Te4S9), as well as evidence of compositional continuity in the compositional range between tetradymite and aleksite. The latter may, however, be the result of fine intergrowths of individual minerals in the system PbNBi4Te4SN+2. Since structural data are lacking for most members of the series, we prefer not to formally define a series at this juncture, but will nevertheless examine evidence favoring its existence and possible explanation of the extensive compositional fields in terms of fine intergrowths.
In their studies of the system Pb–Bi–Te–S, Liu & Chang (1994) found three synthetic phases (D, E and J) of the seven phases they recognized, that correspond to "phase C", aleksite and saddlebackite, respectively. A fourth synthetic phase (F) corresponds to Pb3Bi4Te4S5, the ideal N = 3 member of the series, which had not previously been found in nature, and may be present in the Fragant specimens if the single analysis we report is representative (it may just be coincidental). X-ray powder diffraction was carried out on the four run products (Liu & Chang 1994), allowing calculation of unit-cell data (Table 6). These authors did not synthesize phases with higher Pb or S contents at 500°C, which would correspond to compositions similar to those identified from Iilijärvi or Fragant. In this respect, it is important to note that estimates of metamorphic conditions for amphibolite-facies cordierite–anthophyllite rocks at Orijärvi are 560–620°C at 3–5 kbar (Schreurs & Westra 1985). Our paragenetic observations on the material reveal a sequence of crystallization among Bi-minerals from the metamorphic peak to below the melting point of native bismuth (271°C), raising the possibility that these phases may well be stable at conditions that were not duplicated in the synthetic experiments of Liu & Chang (1994).
Crystal structures
The structures of minerals in the system Bi–Te–Se–S (excepting bismuthinite and guanajuatite) have conventionally been understood in terms of modular combinations of five-atom "tetradymite" units (Bi2X3, where X = Te, Se, S) and two-atom Bi2 units (Cook et al., in press, and references therein). A distinct seven-atom unit has been proposed for rucklidgeite, PbxBi3–xTe4 (0 
x 1), in which the unit cell is composed of three seven-atom layer units "X–Bi–X–Bi–X–Bi–X" (Petrov & Imamov 1970, Imamov et al. 1970, Zhukova & Zaslavskii 1971, 1976, Frangis et al. 1989, 1990). Poubaite, PbBi2(Se,Te,S)4, is considered isotypic with rucklidgeite (Moëlo & Makovicky 2006). A hierarchical series of Pb–Bi tellurosulfides could, therefore, be postulated by combination of the five-atom "tetradymite" unit, and the seven-atom "rucklidgeite-like" unit, with the possibility of extension to nine- and even eleven-atom units in the case of more complex members of the series (Petrov & Imamov 1970). In addition, there exists a possibility of a combinatorial series, in which combinations of layer types can be invoked for structures with odd N values (e.g., "phase C", as a combination of five- and seven-atom layers). Liu & Chang (1994), among others, have found such a structural model compatible with observations. The fact is, however, that few structures are known with any certainty. In structural determinations of kochkarite, PbBi4Te7, for example, Talybov & Vainstein (1961) were unable to fully resolve atom sites and occupancies. The extrapolation of poorly understood structures to other minerals and phases (e.g., the possibility that kochkarite and PbBi4Te4S3, or aleksite and rucklidgeite, might be isostructural pairs) is ill-advised until structural solutions for natural specimens of "phase C", aleksite and saddlebackite are available. In their current review of sulfosalts, Moëlo & Makovicky (2006) placed six Pb-rich species (babkinite, saddlebackite, poubaite, rucklidgeite, aleksite and kochkarite) within the bismuth–tetradymite homologous series, broadly endorsing the stacking periodicity presented here.
Potential for modularity and intergrowths
The lamellar banding of "phase C" and the phase(s) in the Iilijärvi samples, their coexistence, their intergrowth with galena and tetradymite, and the extended compositional fields documented by electron-microprobe analysis are reminiscent of similar variation and intergrowths among some Bi-sulfosalt series (e.g., Pring & Hyde 1987, Pring et al. 1999, Pring 2001, Pring & Etschmann 2002, Ciobanu et al. 2004). Disordered intergrowths of Bi-sulfosalts tend to give characteristic extended compositional fields, not dissimilar to those identified among the Pb–Bi tellurosulfides investigated in the present study. Direct comparison between the Bi– Pb tellurosulfides and sulfosalts is, however, hampered by the lack of structural data for most of the Bi–Pb tellurosulfides. Despite this uncertainty, which may yet be resolved by appropriate HRTEM investigations in the future, degrees of stacking disorder at the lattice scale could viably explain the large spread of compositions within mineral grains that otherwise appear homogeneous. For example, irregular intergrowths of individual members of a modular series (tetradymite, aleksite, "phase C", etc.) in the Clogau samples would give compositional fields like those we report. Presumably, disorder also applies to the phase(s) in the Iilijärvi samples. Indeed, degrees of stacking disorder may even be amplified in Pb- and S-rich varieties, given their possibly much-reduced fields of stability.
A strong affinity among Bi–Pb tellurosulfides, galena and Bi–(Sb) sulfosalts is noted at Iilijärvi. The lamellar bands of aleksite and galena in host giessenite appear to represent an equilibrium assemblage. Similar types of polysomatic disorder are well known in biopyriboles and humite groups (e.g., Veblen & Buseck 1979). The Orijärvi–Iilijärvi area is noted for the occurrence of complex, modular triple- and double-chain biopyriboles (Schumacher & Czank 1987).
Relationship with other related compounds
There are two recognized sulfur-free Pb–Bi–Te compounds (Table 6). Kochkarite is reported from its type locality and from Zod (Spirodonov et al. 1989). Rucklidgeite, PbBi2Te4, was originally defined as (Bi,Pb)3Te4 (Zavyalov & Begizov 1977), and it has since been suggested that the Pb content can vary (e.g., Kase et al. 1993) within the limits PbBi2Te4–Bi3Te4 (Bayliss 1991). Liu & Chang (1994) were able to synthesise kochkarite and rucklidgeite as phases M and A, respectively; a further phase of theirs, ‘K’, Pb2Bi2(Te,S)5, may be related. An unnamed phase, Pb5Bi5Te3S7, reported to be associated with kochkarite in the Kochkar deposit (Spiridonov et al. 1989), is difficult to reconcile with either series.
"Jolotcaite", a Pb–Bi tellurosulfide with the composition PbBi3Te4S3, was described by Damian et al.(1988) from Mesozoic gold-bearing veins from the Jolotca Valley, Ditrau, Romania. X-ray maps of the apparently homogeneous phase were presented, showing the distribution of component elements. The formula, as given, did not match any known mineral or unnamed phase. Damian et al.(2004) showed, however, that this phase is compositionally identical to "phase C", i.e., PbBi4Te4S3. Although more homogeneous areas are identified, the phase appears to be intimately intergrown with aleksite, as in the Clogau specimens. This unusual assemblage also contains lillianite and heyrovsk
ite within a matrix dominantly consisting of pyrite with abundant allanite and monazite. A manuscript is presently in preparation in which the association and chemical composition of the tellurosulfides and sulfosalts will be reported in detail.
Pb-bearing tetradymite
Published electron-microprobe data for tetradymite commonly show the presence of several wt.% Pb (e.g., compositional data for bi–pb tellurosulfides 433 Plimer 1974, Spiridonov et al. 1978). The presence of lead may be caused by the presence of sub-µm inclusions of galena or other lead minerals, but could, alternatively, be real. In the Clogau specimens, we note that tetradymite can contain various amounts of Pb ranging, continuously from zero up to the composition of "phase C" (Fig. 6). Such a range in composition was observed earlier by Naden (1988), causing Bevins & Stanley (1990) to remark that "plumbian tetradymite is probably not tetradymite at all". Future study of the Clogau specimens by the HRTEM technique may reveal whether the observed compositions can be attributed to submicroscopic intergrowths of tetradymite units with Pb–Bi tellurosulfides.
Genetic considerations
We note that most, if not all, occurrences of aleksite, saddlebackite and "phase C" (Clogau, Iilijärvi, Fragant, Boddington, Kockhar, Alekseev) are restricted to deposits that are linked in one way or another to formation or overprinting of a low-temperature assemblage by high-temperature hydrothermal or magmatic fluids. Archean mesothermal gold deposits such as Boddington (Allibone et al. 1998), Paleozoic lode-gold systems such as Kochkar (Kisters et al. 2000), regionally metamorphosed deposits like Clogau, Iilijärvi and Fragant, and skarn systems (Ardino) all fall in this category.
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CONCLUSIONS |
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AKNOWLEDGEMENTS |
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REFERENCES |
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BAYLISS, P. (1991): Crystal chemistry and crystallography of some minerals in the tetradymite group. Am. Mineral. 76, 257–265.[Abstract][ISI][GeoRef]
BERRY, L.J. & THOMPSON, R.H. (1962): X-Ray Powder Data for Ore Minerals. The Peacock Atlas. Geol. Soc. Am., Mem. 85.
BEVINS, R.E. & STANLEY, C.J. (1990): Aleksite, a lead bismuth sulfotelluride; a second world occurrence from the Dolgellau gold belt, Wales. J. Russell Soc. 3(2), 67–69.
BONEV, I.K. & NEYKOV, H.N. (1990): Minerals of silver, bismuth and tellurium in Ardino polymetallic deposit. Bulg. Acad. Sci., Geochim. Mineral. Petrol. 26, 3–19.
BORGSTROM, L.H. (1915): Mineralogiska notiser 7–10. 7. Selenhaltig Lillianit från Iilijärvi. Geol. Fören. Stockholm Förh. 32, 1525–1530.
BOTTRELL, S.H., SHEPHERD, T.J., YARDLEY, B.W.D. & DUBESSY, J. (1988): A fluid inclusion model for the genesis of the ores of the Dolgellau Gold Belt, North Wales. J. Geol. Soc. London 145, 139–145.
BOTTRELL, S.H. & SPIRO, B. (1988): A stable isotope study of black shale-hosted mineralization in the Dolgellau gold belt, North Wales. J. Geol. Soc. London 145, 941–949.
ECH, F. & VAVRIN, I. (1978): Poubaite, PbBi2(Se,Te,S)4, a new mineral. Neues Jahrb. Mineral., Monatsh., 9–19.
CIOBANU, C.L., COOK, N.J. & SUNDBLAD, K. (2002): Genetic insights from exotic trace mineral associations at Orijärvi and Iilijärvi, S.W. Finland. In Metallogeny of Precambrian Shields (Ky’iv, Ukraine), Abstr. Vol., 41–45.
CIOBANU, C.L., PRING, A. & COOK, N.J. (2004): Micron- to nano-scale intergrowths among members of the cuprobismutite series and paderaite: HRTEM and microanalytical evidence. Mineral. Mag. 68, 279–300.
CLARKE, R.M. (1997): Saddlebackite, Pb2Bi2Te2S3, a new mineral species from the Boddington gold deposit, Western Australia. Aust. J. Mineral. 3, 119–124.
COOK, N.J., CIOBANU, C.L., WAGNER, T. & STANLEY, C.J. (2007): Minerals of the system Bi–Te–Se–S related to the tetradymite archetype: review of classification and compositional variation. Can. Mineral. 45 (in press).
CRIDDLE, A.J. & STANLEY, C.J., eds. (1986): The Quantitative Data File for Ore Minerals (2nd edition). IMA/COM. British Museum (Natural History), London, U.K.
DAMIAN, G., COOK, N.J., CIOBANU, C.L., POP, N. & RAUDSEPP, M. (2004): Pb–Bi tellurides from Mo–gold–pyrite veins associated with alkaline magmatism: compositional and genetic constraints. Int. Geol. Congress, 32nd (Florence), Abstr.
DAMIAN, G., POP, N. & GARBASEVSCHI, N. (1988): A new lead and bismuth sulpho-telluride identified at Jolotca–Ditrau. Rev. Roum. Geol., Geophys. Geogr., Ser. Geol., 32, 3–8.
DE SOUZA LIMA, R.F., MIZUTA, T., ISHIYAMA, D. & FUJITA, T. (1996): Tellurium-bearing minerals in Corrego Criminoso gold mining district, Goias State, Brazil. Rep., Res. Inst. of Natural Resources, Mining College, Akita Univ. 61, 1–16.
ESKOLA, P.E. (1914); On the petrology of the Orijärvi region in southwestern Finland. Bull. Comm. Géol. Finlande 40.
ESKOLA, P.E. (1915): Om sambandet mellan kemisk och mineralogisk sammansättning hos Orijärvi traktens metamorfa bergarter. Bull. Comm. Géol. Finlande 44, 109–145.
ESKOLA, P.E. (1950): Orijärvi re-interpreted. Bull. Comm. Géol. Finlande 150, 93–102.
FRANGIS, N., KUYPERS, S., MANOLIKAS, C., VAN LANDUYT, J. & AMELINCKX, S. (1989): Continuous series of one-dimensional structures in the compounds Bi2+xSe3, Bi2+xTe3, Sb2+xTe3, (Bi2Te3)nGeTe and (Sb2Te3)nGeTe. Solid State Commun. 69, 817–819.[CrossRef]
FRANGIS, N., KUYPERS, S., MANOLIKAS, C., VAN TENDELOO, G. & AMELINCKX, S. (1990): Continuous series of onedimensional structures in compounds based on M2X3 (M = Sb, Bi, X = Se, Te). J. Solid State Chem. 84, 314–334.[CrossRef]
GILBEY, J.W.G. (1968): The Mineralogy, Paragenesis and Structure of the Ores of the Dolgellau Gold Belt, Merionithshire, and Associated Wall-rock Alteration. Ph.D. thesis, Univ. of London, U.K.
IMAMOV, R.M., SEMILETOV, S.A. & PINSKER, Z.G. (1970): The crystal chemistry of semiconductors with octahedral and with mixed atomic coordination. Kristallografiya 15, 287–293 (in Russ.).
KASE, K., KUSACHI, I. & KISHI, S. (1993): Rucklidgeite solid-solution in the Yanahara deposit, Japan. Can. Mineral. 31, 99–104.
KISTERS, A.F.M., MEYER, F.M., ZNAMENSKY, S.E., SERAVKIN, I.B., ERTL, R.G.W. & KOSAREV, A.M. (2000): Structural controls of lode-gold mineralization by mafic dykes in late-Paleozoic granitoids of the Kochkar district, southern Urals, Russia. Mineral. Deposita 35, 157–168.[CrossRef]
LAITAKARI, A. (1934): Orijärven vismuttimineraaleista. Eripainos Suomen Kemistilehdestä 9, 90–92 (in Finnish).
LIPOVETSKIY, A.G., BORODAEV, YU.S. & ZAV'YALOV, YE.N. (1976): New lead–bismuth tellurides of the Alekseyev ore show (Stanovoy range). Geol. Rudn. Mestorozh. 18, 111–115 (in Russ.). [English translation in Int. Geol. Rev. (1978) 19, 1230–1234.]
LIPOVETSKIY, A.G., BORODAEV, YU.S. & ZAV'YALOV, YE.N. (1978): Aleksite, PbBi2Te2S2, a new mineral. Zap. Vses. Mineral. Obshchest. 107, 315–321 (in Russ.). [English translation in Int. Geol. Rev. (1979) 21, 1223–1228.]
LIU, H. & CHANG, L.L.Y. (1994): Lead and bismuth chalcogenide systems. Am. Mineral. 79, 1159–1166.[Abstract][ISI][GeoRef]
MASON, J.S., FITCHES, W.R. & BEVINS, R.E. (1999): Evidence of a pre-tectonic origin for the auriferous vein-type mineralization of the Dolgellau gold belt, North Wales. Trans. Inst. Mining Metall. B108, 45–52.
MAKELA, U. (1989): Geological and geochemical environments of Precambrian sulphide deposits in southwestern Finland. Annales Academiae Scientiarum Fennicae, Ser. A. III. Geologica-Geographica 151.
MOELO, Y. & MAKOVICKY, E. (2006): Report of the Sulfosalt Subcommittee of the IMA Commission on Ore Mineralogy. International Mineralogical Association (Kobe), 19th General Meeting.
NADEN, J. (1988): Gold Mineralization in the Caledonides of the British Isles with Special Reference to the Dolgellau Gold Belt, North Wales and the Southern Uplands, Scotland. Ph.D. thesis, Univ. of Aston, Birmingham, U.K.
PAAR, W.H. (2000): Montangeologie des Tauerngoldes. In Schatzkammer Hohe Tauern: 2000 Jahre Goldbergbau (W. Günther & W.H. Paar, eds.). Anton Pustet, Salzburg, Austria (301–366).
PAULING, L. (1975): The formula, structure, and chemical bonding of tetradymite, Bi14Te13S8, and the phase Bi14Te15S8. Am. Mineral. 60, 994–997.[ISI][GeoRef]
PETROV, I.I. & IMAMOV, P.M. (1970): Electron-diffraction analysis of PbTe–Bi2Te3 system phases. Sov. Phys. Crystallogr. 14, 593–596.
PLATTEN, I.M. & DOMINY, S.C. (1999): Re-evaluation of quartz vein history in the Dolgellau gold-belt, North Wales, United Kingdom. Geol. J. 34, 369–391.[CrossRef]
PLIMER, I.R. (1974): Plumbian tetradymite – csiklovaite – bismuthinite reaction from Wolfram Camp, North Queensland, Australia. Neues Jahrb. Mineral., Monatsh., 316–323.
PRING, A. (2001): The crystal chemistry of the sartorite group minerals from Lengenbach, Binntal, Switzerland – a HRTEM study. Schweiz. Mineral. Petrogr. Mitt. 81, 69–87.
PRING, A. & ETSCHMANN, B. (2002): HRTEM observations of structural and chemical modulations in cosalite and its relationship to the lillianite homologues. Mineral. Mag. 66, 451–458.
PRING, A. & HYDE, B.G. (1987): Structural disorder in lindströmite: a bismuthinite–aikinite derivative. Can. Mineral. 25, 393–399.
PRING, A., JERCHER, M. & MAKOVICKY, E. (1999): Disorder and compositional variation in the lillianite homologous series. Mineral. Mag. 63, 917–926.[Abstract][CrossRef][ISI][GeoRef]
PUTZ, H., PAAR, W.H., TOPA, D., HORNER, J. & LUDERS, V. (2003): Structurally controlled gold and sulfosalt mineralization: the Altenberg example, Salzburg Provice, Austria. Mineral. Petrol. 78, 111–138.[CrossRef]
ROCHATA, C. (1878): Die alten Bergbaue auf Edelmetalle in Oberkärnten. Jahrb. d. k. k. geol. Reichsanstalt, 28(2), 213–368.
SCHREURS, J. & WESTRA, L. (1985): Cordierite–orthopyroxene rocks: the granulite facies equivalents of the Orijärvi cordierite–anthophyllite rocks in West Uusimaa, southwest Finland. Lithos 18, 215–228.[CrossRef]
