The evolution of the Kaapvaal craton: A multi-isotopic perspective from lithospheric peridotites from Finsch diamond mine
文献类型:期刊论文
作者 | Qiao Shu; Gerhard P. Brey; D. Graham Pearson; Jingao Liu; Sally A. Gibson; Harry Becker |
刊名 | Precambrian Research
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出版日期 | 2019 |
卷号 | 331页码:1-21 |
关键词 | Mantle depletion Mantle Metasomatism hse metasomatic Bms archean Mantle |
英文摘要 | Accurately dating the formation and modification of Earth’s sub-cratonic mantle still faces many challenges, primarily due to the long and complex history of depletion and subsequent metasomatism of this reservoir. In an attempt to improve this, we carried out the first study on peridotites from the Kaapvaal craton (Finsch Mine) that integrates results from Re-Os, Lu-Hf, Sm-Nd and Sr-isotope systems together with analyses of major-, trace- and platinum-group elements. The Finsch peridotites are well-suited for such a study because certain compositional features reflect they were highly depleted residues of shallow melting (1.5 GPa) at ambient Archean mantle temperatures. Yet, many of them have overabundant orthopyroxene, garnet and clinopyroxene compared to expected modal amounts for residues from partial melting. Finsch peridotites exhibit a wide range of rhenium depletion ages (TRD) from present day to 2.7 Ga, with a prominent mode at 2.5 Ga. This age overlaps well with a Lu-Hf isochron of 2.64 Ga (εHf (t) = +26) which records silico-carbonatitic metasomatism of the refractory residues. This late Archean metasomatism is manifested by positive correlations of Pt/Ir and Pd/Ir with 187Os/188Os ratios and good correlations of modal amounts of silicates, especially garnet, with Os isotope ratios. These correlations suggest that the Highly Siderophile Elements (HSE) and incompatible element reenrichment and modal metasomatism result from one single major metasomatic event at late Archean. Our detailed study of Finsch peridotites highlights the importance of using multiple isotopic systems, to constrain the ages of events defining the evolution of lithospheric mantle. The Re-Os isotope system is very effective in documenting the presence of Archean lithosphere, but only the oldest TRD ages may accurately date or closely approach the age of the last major partial melting event. For a meaningful interpretation of the Re-Os isotope systematics the data must be combined with HSE patterns, trace-element compositions and ideally other isotopic systems, e.g. Lu-Hf. This is highlighted by the widespread evidence in Finsch peridotites of Pt, Pd and Re enrichment through significant Base Metal Sulfide (BMS) addition (mainly in the range of 0.002–0.08 wt%) that systematically shifts the mode of TRD model ages to younger ages. |
语种 | 英语 |
源URL | [http://ir.gyig.ac.cn/handle/42920512-1/10595] ![]() |
专题 | 地球化学研究所_矿床地球化学国家重点实验室 |
作者单位 | 1.Institut für Geologische Wissenschaften, Freie Universität Berlin, Berlin, Germany 2.State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China 3.State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China 4.Dept. of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Canada 5.CAS Center for Excellence in Comparative Planetology, China 6.Institut für Geowissenschaften, Mineralogie, J. W. Goethe-Universität Frankfurt, Frankfurt, Germany 7.Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, United Kingdom |
推荐引用方式 GB/T 7714 | Qiao Shu;Gerhard P. Brey;D. Graham Pearson;Jingao Liu;Sally A. Gibson;Harry Becker. The evolution of the Kaapvaal craton: A multi-isotopic perspective from lithospheric peridotites from Finsch diamond mine[J]. Precambrian Research,2019,331:1-21. |
APA | Qiao Shu;Gerhard P. Brey;D. Graham Pearson;Jingao Liu;Sally A. Gibson;Harry Becker.(2019).The evolution of the Kaapvaal craton: A multi-isotopic perspective from lithospheric peridotites from Finsch diamond mine.Precambrian Research,331,1-21. |
MLA | Qiao Shu;Gerhard P. Brey;D. Graham Pearson;Jingao Liu;Sally A. Gibson;Harry Becker."The evolution of the Kaapvaal craton: A multi-isotopic perspective from lithospheric peridotites from Finsch diamond mine".Precambrian Research 331(2019):1-21. |
入库方式: OAI收割
来源:地球化学研究所
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