Nature of graphitization and noble metal mineralization in metamorphic rocks of the northern Khanka Terrane, Primorye

Ханчук, А. И.; Plyusnina, L. P.; Ruslan, A. V.; Likhoidov, G. G.; Barinov, N. N.

doi:10.1134/s1075701513040041

Cited by 9 publications

(2 citation statements)

References 13 publications

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“…As it follows from our experiments, carbon (graphite) will adsorb Pt carbonyl and may contribute to the concentration of the diluted relative PGE natural fluids. The origin of graphitized rocks enriched in PGE and Au [43] may be related to this process.…”

Section: Discussionmentioning

confidence: 99%

Experimental Study of Pt Solubility in the CO-CO2 Fluid at Low fO2 and Subsolidus Conditions of the Ultramafic-Mafic Intrusions

et al. 2021

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The solubility of Pt in CO-CO2 fluid was studied experimentally at P = 50–200 MPa and T = 950 °C. A mixture of MgC2O4 and MgCO3 was used as a source of the fluid. Upon the reaction of the Pt capsule walls and the fluid, a carbonyl of platinum is formed. The use of the high-temperature quartz ceramics as a fluid trap avoids the effect of mechanical contamination with Pt from the eroded capsule walls. The total content of platinum in the porous fluid traps was measured by the Electrothermal Atomic Absorption (ET-AAS) method. In some experiments, the local analysis of traps was carried out by the Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) method. The composition of fluid in bubbles captured in an albite glass trap was studied by micro-Raman spectroscopy. On the capsule walls and MgO, Pt “whiskers” of submicron diameter were observed, which were formed as a product of carbonyl decomposition during quenching. About 5–15% of carbonyl withstands quenching resulting in 1.5 to 2 ppm Pt soluble in acetone (runs at P = 200 MPa) in a quartz glass trap. The amount of Pt soluble in acetone from the capsule walls corresponds to a concentration of up to 8 ppm in the fluid. A high content of soluble Pt of 2000–3000 ppm was determined in a carbon coated MgO matrix. Our study demonstrated that the solubility of Pt in the CO-CO2 fluid is 15–150 ppm, presumably in the form of Pt3(CO)62− under conditions corresponding to the conditions of the subsolidus stage of layered ultramafic-mafic and ultramafic-alkaline intrusions formation. Our preliminary data showed that this solubility will increase with the addition of water at low fO2.

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Section: Discussionmentioning

confidence: 99%

Experimental Study of Pt Solubility in the CO-CO2 Fluid at Low fO2 and Subsolidus Conditions of the Ultramafic-Mafic Intrusions

et al. 2021

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“…Therefore, we conclude that the Xujiahe Formation is the most likely origin for the CMs in the CMVs. We also consider other possible origins of CMs: (1) CMs are possibly deposited from C-O-H fluids migrating in along the fault zone by changes in the physical-chemical conditions (e.g., Khanchuk et al 2013;Mathez et al 1995;Pasteris and Chou. 1998), but we did not find other minerals deposited together with the CMs yet, and (2) the CMs might be the product of the chemical reaction CO 2 + CH 4 → 2C + 2H 2 O due to coseismic frictional heating (Mathez et al 2008), as CH 4 and CO 2 are the predominant components of gas emission measured along the YBF both before (Du et al 2006) and after the Wenchuan earthquake (Zheng et al 2013;Zhou et al, 2010).…”

Section: Origin Of Cms For the Cmvsmentioning

confidence: 99%

Origin and formation of carbonaceous material veins in the 2008 Wenchuan earthquake fault zone

Jiang

Zhang

et al. 2016

Earth Planet Sp

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This paper establishes a reference data set of carbonaceous materials (CMs) from the active fault zone of the Longmen Shan fault belt that ruptured in the 2008 Mw7.9 Wenchuan earthquake and presents an application of these data for studies of both other exhumed carbonaceous-rich fault zones and deep-drilling cores. The CMs distributed in the active fault zone are found as narrow veins and located along the slip surfaces. Microstructural observation shows that the carbonaceous material veins (CMVs) are located along slip surfaces in the fault gouge zones. Some CMVs have a cataclastic fabric, and their branches intrude into voids around the slip surfaces. Raman spectra of the CMVs show a wide (full width at half maximum >200 cm −1 ) D-peak at~1345 cm −1 (defect peak), which is much lower than the O-peak at~1595 cm −1 (ordered peak), indicating a metamorphic temperature of zeolite facies or lower than 250°C. In addition, the stable carbon isotopic compositions (δ 13 C values) of the CMVs, ranging from −23.4 to −26.4‰, are very similar to that of the kerogen collected from the Late Triassic Xujiahe Formation in Sichuan Basin. Given the data at which it may be formed, the Xujiahe Formation is the most likely origin of CMs for the CMVs, and it seems that some CMVs in the fault zone were crushed and intruded into the voids during coseismic events, possibly driven by an enhanced pore fluid pressure. Since graphitization is suggested as an indicator of transient frictional heating in this area, our study providing a reference data set of CMs would help future CM-rich fault-zone research to retrieve seismic signatures presumably occurring in the Longmen Shan fault zone belt.

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Reduced carbonic fluid and possible nature of high-K magmas of Tolbachik

Simakin

Salova

Devyatova

et al. 2015

Journal of Volcanology and Geothermal Research

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Nature of graphitization and noble metal mineralization in metamorphic rocks of the northern Khanka Terrane, Primorye

Cited by 9 publications

References 13 publications

Experimental Study of Pt Solubility in the CO-CO2 Fluid at Low fO2 and Subsolidus Conditions of the Ultramafic-Mafic Intrusions

Experimental Study of Pt Solubility in the CO-CO2 Fluid at Low fO2 and Subsolidus Conditions of the Ultramafic-Mafic Intrusions

Origin and formation of carbonaceous material veins in the 2008 Wenchuan earthquake fault zone

Reduced carbonic fluid and possible nature of high-K magmas of Tolbachik

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