On the Isotopic Composition of Carbon in Epigenetic Graphites

Chukhrov, F. V.; Ermilova, L. P.; Nosik, L. P.

doi:10.1007/978-3-642-70074-3_12

Cited by 4 publications

(6 citation statements)

References 8 publications

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“…Despite Rao and Adusumilli (1965) [4] finding no correlation between the data they obtained and those of Chukhrov et al (1960) [55], the current study has found a clear overlap between 865 and 875˝C ( Figure 6). The double endothermic spike is shifted to slightly higher temperatures compared to Chukhrov et al (1960) [55], possibly due to the effect of trace amounts of preisingerite.…”

Section: Comparison Of Analytical Resultscontrasting

confidence: 90%

“…Only scarce information is available regarding thermal experiments on bismuth oxychlorides. Chukhrov et al (1960) [55] reported a curve for bismoclite which shows characteristic peaks at 625-675˝C and 825-875˝C [4], whereas Rao and Adusumilli (1965) [4] studied a bismoclite sample from Brazil and observed only one endothermic curve between 920 and 930˝C prior to material fusion at 945˝C (Table 7). Despite Rao and Adusumilli (1965) [4] finding no correlation between the data they obtained and those of Chukhrov et al (1960) [55], the current study has found a clear overlap between 865 and 875˝C ( Figure 6).…”

Section: Comparison Of Analytical Resultsmentioning

confidence: 99%

“…Chukhrov et al (1960) [55] reported a curve for bismoclite which shows characteristic peaks at 625-675˝C and 825-875˝C [4], whereas Rao and Adusumilli (1965) [4] studied a bismoclite sample from Brazil and observed only one endothermic curve between 920 and 930˝C prior to material fusion at 945˝C (Table 7). Despite Rao and Adusumilli (1965) [4] finding no correlation between the data they obtained and those of Chukhrov et al (1960) [55], the current study has found a clear overlap between 865 and 875˝C ( Figure 6). The double endothermic spike is shifted to slightly higher temperatures compared to Chukhrov et al (1960) [55], possibly due to the effect of trace amounts of preisingerite.…”

Section: Comparison Of Analytical Resultsmentioning

confidence: 99%

“…BiOCl [55] Characteristic peak: 625-675˝C Characteristic peak: 825-875˝C Naturally occurring BiOCl [4] Endothermic peak: 920-930˝C Characteristic peak: 945˝C (fusion) Synthetic BiOCl [56] Exothermic peak and sharp mass loss: >600˝C (BiOCl decomposition) [59] verified the temperature range of α-to δ-Bi 2 O 3 transitions with in-situ Raman spectroscopy, XRD, DTA and impedance spectroscopy (IS). During the DTA heating process, they only detected one transition from the monoclinic α-to δ-Bi 2 O 3 at 727˘2˝C before reaching its melting point at 822˘3˝C (Table 7).…”

Section: Biocl Naturally Occurringmentioning

confidence: 90%

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Bismoclite (BiOCl) in the San Francisco de los Andes Bi–Cu–Au Deposit, Argentina. First Occurrence of a Bismuth Oxychloride in a Magmatic–Hydrothermal Breccia Pipe and Its Usefulness as an Indicator Phase in Mineral Exploration

et al. 2016

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Abstract:The rare bismuth oxychloride, bismoclite (BiOCl), has been identified in the weathered tourmaline-cemented, magmatic-hydrothermal breccia complex at the San Francisco de los Andes Bi-Cu-Au deposit, Argentina. A wide variety of supergene minerals were detected in the oxidized zone, but only preisingerite (Bi 3 (AsO 4 ) 2 O(OH)) is intimately associated with bismoclite. Bismuth arsenate is present either as minor accessory phases or as traces in bismoclite-rich samples. This is the first documented occurrence of bismoclite in a porphyry-related, and magmatic-hydrothermal breccia pipe deposit. Bismoclite is interpreted to have formed by weathering of hypogene bismuthinite (Bi 2 S 3 ), which originally occurred with arsenopyrite to cement the breccias. These appear to have reacted with O 2 -and HCl-bearing meteoric waters to produce pockets of supergene bismoclite-preisingerite assemblages. Bismoclite samples have been characterized by means of X-ray diffractometry (XRD), geochemistry, petrography, scanning electron microscopy (SEM), differential thermal analysis-thermogravimetry analysis (DTA-TGA) and infrared analysis (IR) providing useful insights and updated information regarding this rare bismuth oxychloride and associated arsenate mineral. The San Francisco de los Andes breccia complex shows similar geometry, morphology and internal organization as those found in traditional magmatic-hydrothermal breccias associated with Cu-Mo porphyry deposits. Bismoclite and preisingerite form due to the presence of hypogene Bi-bearing minerals followed by appropriate supergene conditions. These hypogene minerals commonly occur only as trace phases, or are entirely absent, in porphyry and related magmatic-hydrothermal breccia deposits. The scarcity of hypogene Bi-mineral phases in porphyry and related magmatic-hydrothermal breccia deposits is the main reason why bismoclite has not previously been reported in these types of deposits. The detection of bismoclite as a mineral phase in the oxidized zone of weathered deposits highlights hypogene Bi mineralization at depth, and associated metals. Bismoclite is an insoluble mineral of particular interest in those supergene profiles which have been completely leached out of distinctive, water-soluble phases, such as Cu sulfate minerals, which are diagnostic of Cu mineralization at depth. Consequently, bismoclite could potentially be the only indicator of hypogene and supergene mineralization in lower portions of a bismuth bearing ore deposit.

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Section: Comparison Of Analytical Resultscontrasting

confidence: 90%

Section: Comparison Of Analytical Resultsmentioning

confidence: 99%

Section: Comparison Of Analytical Resultsmentioning

confidence: 99%

Section: Biocl Naturally Occurringmentioning

confidence: 90%

See 2 more Smart Citations

Bismoclite (BiOCl) in the San Francisco de los Andes Bi–Cu–Au Deposit, Argentina. First Occurrence of a Bismuth Oxychloride in a Magmatic–Hydrothermal Breccia Pipe and Its Usefulness as an Indicator Phase in Mineral Exploration

et al. 2016

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“…The volcanic host rocks of the Borrowdale Volcanic Group show field, mineralogical, and geochemical evidence of assimilation of metapelitic material from the underlying Skiddaw Group (Ortega et al 2010). The process of assimilation of carbonaceous materials increases the carbon content of the magma and appears to play a key role in the formation of many graphite deposits hosted by igneous rocks as recently reported by Luque et al (2012a) for graphite mineralization in volcanic settings and by Chukhrov et al (1984) for vein graphite in nepheline syenites from the Botogol massif.…”

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confidence: 56%

Vein graphite deposits: geological settings, origin, and economic significance

et al. 2013

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Graphite deposits result from the metamorphism of sedimentary rocks rich in carbonaceous matter or from precipitation from carbon-bearing fluids (or melts). The latter process forms vein deposits which are structurally controlled and usually occur in granulites or igneous rocks. The origin of carbon, the mechanisms of transport, and the factors control-ling graphite deposition are discussed in relation to their geological settings. Carbon in granulite-hosted graphite veins derives from sublithospheric sources or from decarbonation reactions of carbonate-bearing lithologies, and it is transported mainly in CO 2 -rich fluids from which it can precipitate. Graphite precipitation can occur by cooling, water removal by retrograde hydration reactions, or reduction when the CO 2 -rich fluid passes through relatively low-fO 2 rocks. In igneous settings, carbon is derived from assimilation of crustal mate-rials rich in organic matter, which causes immiscibility and the formation of carbon-rich fluids or melts. Carbon in these igneous-hosted deposits is transported as CO 2 and/or CH 4 and eventually precipitates as graphite by cooling and/or by hydration reactions affecting the host rock. Independently of the geological setting, vein graphite is characterized by its high purity and crystallinity, which are required for applica-tions in advanced technologies. In addition, recent discovery of highly crystalline graphite precipitation from carbon-bearing fluids at moderate temperatures in vein deposits might provide an alternative method for the manufacture of synthetic graphite suitable for these new applications.

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