Recent fluid processes in the Kaapvaal Craton, South Africa: coupled oxygen isotope and trace element disequilibrium in polymict peridotites
文献类型：期刊论文
| 作者 | Zhang, HF; Mattey, DP; Grassineau, N; Lowry, D; Brownless, M; Gurney, JJ; Menzies, MA |
| 刊名 | EARTH AND PLANETARY SCIENCE LETTERS
 |
| 出版日期 | 2000-02-28 |
| 卷号 | 176期号:1页码:57-72 |
| 关键词 | Kaapvaal Craton diffusion O-18/O-16 trace elements peridotites equilibrium |
| ISSN号 | 0012-821X |
| 文献子类 | Article |
| 英文摘要 | Oxygen-isotope mapping of thin sections of polymict peridotite xenoliths shows that significant oxygen isotope disequilibrium is preserved on a sub-millimetre scale in primary and secondary minerals. Primary porphyroblastic phases (e.g., olivine, orthopyroxene, garnet, diopside) tend to have higher delta(18)O ratios than secondary minerals (e.g., mica, ilmenite, neoblastic olivine, orthopyroxene rims). Polymict minerals have a lower oxygen isotope composition than 'average mantle' (delta(18)O=5.2+/-0.3 parts per thousand) and show clear evidence of inter- and intra-mineral oxygen isotope disequilibrium. Disequilibrium is also evident in the elemental geochemistry of the mantle minerals and a general correlation exists between oxygen isotopes and major (Si, Mg, Ca, Fe) and trace elements (Ce, Cr, Zr, Nb, REE). The interpretation that isotopic heterogeneity may relate to melt processes is supported by delta(18)O zonation in garnets, significant isotopic variation close to secondary veins, delta(18)O (primary phases) > delta(18)O (secondary phases) and oxygen isotope disequilibria in many minerals. In addition, a positive correlation between delta(18)O and grain size indicates a role for deformation processes as a result of diffusion reactions perhaps inextricably linked to melt processes. We suggest that polymict peridotites formed as a result of movement along mantle shear zones which led to the juxtaposition of minerals of varied provenance. Contemporaneous melt transfer reacted with these mantle breccias and rapid entrainment by 'kimberlite' meant that any associated mineral disequilibrium was very effectively preserved. (C) 2000 Elsevier Science B.V. All rights reserved. |
| WOS关键词 | RE-OS ISOTOPE ; CARBONATITE METASOMATISM ; LITHOSPHERIC MANTLE ; ENRICHED MANTLE ; HIGH-PRECISION ; IGNEOUS ROCKS ; XENOLITHS ; SYSTEMATICS ; KIMBERLITE ; MINERALS |
| WOS研究方向 | Geochemistry & Geophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:000085728400006 |
| 出版者 | ELSEVIER SCIENCE BV |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/76185]  |
| 专题 | 中国科学院地质与地球物理研究所 |
| 通讯作者 | Zhang, HF |
| 作者单位 | 1.Univ London, Royal Holloway & Bedford New Coll, Dept Geol, Egham TW20 0EX, Surrey, England 2.Chinese Acad Sci, Inst Geol & Geophys, Lab Lithosphere & Tecton Evolut, Beijing 100029, Peoples R China 3.Univ Cape Town, ZA-7925 Cape Town, South Africa |
| 推荐引用方式 GB/T 7714 | Zhang, HF,Mattey, DP,Grassineau, N,et al. Recent fluid processes in the Kaapvaal Craton, South Africa: coupled oxygen isotope and trace element disequilibrium in polymict peridotites[J]. EARTH AND PLANETARY SCIENCE LETTERS,2000,176(1):57-72. |
| APA | Zhang, HF.,Mattey, DP.,Grassineau, N.,Lowry, D.,Brownless, M.,...&Menzies, MA.(2000).Recent fluid processes in the Kaapvaal Craton, South Africa: coupled oxygen isotope and trace element disequilibrium in polymict peridotites.EARTH AND PLANETARY SCIENCE LETTERS,176(1),57-72. |
| MLA | Zhang, HF,et al."Recent fluid processes in the Kaapvaal Craton, South Africa: coupled oxygen isotope and trace element disequilibrium in polymict peridotites".EARTH AND PLANETARY SCIENCE LETTERS 176.1(2000):57-72. |
入库方式： OAI收割
来源：地质与地球物理研究所
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