气候变化领域集成服务门户(CCPortal): Redox-controlled olivine-sulfide equilibration of the Shitoukengde Ni-Cu deposit in Qinghai-Tibet Plateau and its implications

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DOI	10.1007/s00126-023-01215-6
	Redox-controlled olivine-sulfide equilibration of the Shitoukengde Ni-Cu deposit in Qinghai-Tibet Plateau and its implications
	Mao, Ya-Jing; Zheng, Xuyang; Pan, Tong; Yuan, Fanglin; Huang, Hua-Liang; Qin, Ke-Zhang
发表日期	2024
ISSN	0026-4598
EISSN	1432-1866
起始页码	577
结束页码	599
卷号	59 期号:3
英文摘要	Olivine (Fo80-88) from the Shitoukengde deposit exhibits low levels of Ca, Cr, and Al (< 220 ppm) and varying Ni content. The low Ca-Cr-Al contents in olivine and subsolidus temperatures (600-900 degrees C) indicated by olivine-spinel thermometers align with subsolidus equilibria, emphasizing substantial postcumulus modifications. Therefore, the postcumulus effect must be considered when applying olivine-spinel oxybarometers to intrusive rocks. Back-calculating the spinel Fe-Mg contents to magmatic temperature, the estimated oxidation fugacity (fO(2)) range between FQM - 1.5 and FQM - 3.0, approximately 0.5 to 1.5 Delta FQM more reduced compared to those calculated from the raw spinel composition. Moreover, the fO(2) aligns with results obtained from the olivine-sulfide pair (FMQ - 3.0 to FMQ 0). The considerably reducing state and wide oxidation variation are consistent with the graphite occurrence within the reduced intervals and the systematic fO(2) indicated by olivine V/Sc ratios. Combined with the wide olivine Ni range (200-1500 ppm) and the restricted Ni tenor in coexisting sulfides, those findings imply that the olivine-sulfide interaction was predominantly controlled by fO(2). Diffusion modeling at magmatic temperatures reveals that the core-level Fe-Ni re-equilibration after crystallization requires hundreds of years. The homogeneous olivine composition suggests that re-equilibrium has been achieved in Shitoukengde. However, in fast cooling systems, olivine may record the status approaching olivine-sulfide equilibration, leading to extensive intragrain Ni variation (up to 1000 ppm). This study highlights that extreme Ni depletion in olivine from sulfide-bearing rocks is a sign of reducing conditions. Strongly Ni-rich olivine, such as those in the Kevitsa deposit, could result from interaction with high-Ni tenor sulfides at oxidizing conditions.
关键词	Magmatic Ni-Cu deposit Oxidation state Olivine-spinel oxybarometer Sulfide-olivine interaction Re-equilibration East Kunlun
英文关键词	SPINEL OXYGEN GEOBAROMETER; VOISEYS BAY INTRUSION; KUNLUN OROGENIC BELT; ALBANY-FRASER OROGEN; OXIDATION-STATE; CO DEPOSIT; EXPERIMENTAL CALIBRATION; DIFFUSION-COEFFICIENTS; PHASE-EQUILIBRIA; TRACE-ELEMENTS
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:001091159600003
来源期刊	MINERALIUM DEPOSITA
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/283491
作者单位	Chinese Academy of Sciences; Institute of Geology & Geophysics, CAS; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS
推荐引用方式 GB/T 7714	Mao, Ya-Jing,Zheng, Xuyang,Pan, Tong,et al. Redox-controlled olivine-sulfide equilibration of the Shitoukengde Ni-Cu deposit in Qinghai-Tibet Plateau and its implications[J],2024,59(3).
APA	Mao, Ya-Jing,Zheng, Xuyang,Pan, Tong,Yuan, Fanglin,Huang, Hua-Liang,&Qin, Ke-Zhang.(2024).Redox-controlled olivine-sulfide equilibration of the Shitoukengde Ni-Cu deposit in Qinghai-Tibet Plateau and its implications.MINERALIUM DEPOSITA,59(3).
MLA	Mao, Ya-Jing,et al."Redox-controlled olivine-sulfide equilibration of the Shitoukengde Ni-Cu deposit in Qinghai-Tibet Plateau and its implications".MINERALIUM DEPOSITA 59.3(2024).