| Controls on PGE fractionation in the Emeishan picrites and basalts: Constraints from integrated lithophile-siderophile elements and Sr-Nd isotopes | |
Chusi Li; Yan Tao ; Liang Qi; Edward M.Ripley
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| 2012 | |
| Source Publication | Geochimica et Cosmochimica Acta
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| Volume | 90Issue:1Pages:12-32 |
| Abstract | Picrites from the Emeishan large igneous province (ELIP) may be divided into those that show LREE enrichment and those that are characterized by LREE depletion. All picrite types have low Sr-87/Sr-86 ratios (<0.7057) but variable epsilon(Nd), suggesting that crustal contamination has been negligible, and source mantle variation is responsible for their chemical diversity. In contrast, coeval basalts show strong signatures of crustal contamination. Calculated mantle potential temperatures are 240 degrees C higher than that in ambient mantle, supporting a plume origin for the province. A depleted plume source and ancient sub-continental lithospheric mantle are inferred to be the most important end-members involved in the generation of the Emeishan picrites. Pt and Pd values of the picrites show no evidence of depletion; Pt/Pd ratios are highly variable and show no correlation with picrite type. PGE analyses of both picrites and coeval basalts confirm that Os, Ir, and Ru (IPGE) have behaved compatibly and Pt, Pd, and Rh have behaved incompatibly during Cr-spinel and olivine crystallization. PGE-depleted basalts are present in the ELIP, but the most fractionated basalts tend not to show significant depletion in Pt and Pd. This suggests that fractional crystallization alone was not sufficient to induce sulfide saturation in the magmas, and that contamination involving crustal sulfur was an important driving mechanism. Significant depletion of Ir relative to Ru in some of the basalts regardless of the sulfide saturation state of the parental magma suggests that Ir-dominant alloys segregated prior to magma eruption. Depletions of IPGE relative to Pt and Pd in the Emeishan picrites are consistent with the notion that IPGE alloys are stable in the mantle during partial melting. (C) 2012 Elsevier Ltd. All rights reserved. |
| Subject Area | 矿床地球化学 |
| Indexed By | SCI |
| Language | 英语 |
| Document Type | 期刊论文 |
| Identifier | http://ir.gyig.ac.cn/handle/352002/7100 |
| Collection | 矿床地球化学国家重点实验室_矿床地球化学国家重点实验室_期刊论文 矿床地球化学国家重点实验室 |
| Recommended Citation GB/T 7714 | Chusi Li,Yan Tao,Liang Qi,et al. Controls on PGE fractionation in the Emeishan picrites and basalts: Constraints from integrated lithophile-siderophile elements and Sr-Nd isotopes[J]. Geochimica et Cosmochimica Acta,2012,90(1):12-32. |
| APA | Chusi Li,Yan Tao,Liang Qi,&Edward M.Ripley.(2012).Controls on PGE fractionation in the Emeishan picrites and basalts: Constraints from integrated lithophile-siderophile elements and Sr-Nd isotopes.Geochimica et Cosmochimica Acta,90(1),12-32. |
| MLA | Chusi Li,et al."Controls on PGE fractionation in the Emeishan picrites and basalts: Constraints from integrated lithophile-siderophile elements and Sr-Nd isotopes".Geochimica et Cosmochimica Acta 90.1(2012):12-32. |
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