In situ U-Pb Dating and Sr-Nd Isotopic Analysis of Perovskite: Constraints on the Age and Petrogenesis of the Kuruman Kimberlite Province, Kaapvaal Craton, South Africa
文献类型：期刊论文
| 作者 | Donnelly, Cara L.1; Griffin, William L.1; Yang, Jin-Hui1,2; O'Reilly, Suzanne Y.1; Li, Qiu-Li2; Pearson, Norman J.1; Li, Xian-Hua2 |
| 刊名 | JOURNAL OF PETROLOGY
 |
| 出版日期 | 2012-12-01 |
| 卷号 | 53期号:12页码:2497-2522 |
| 关键词 | kimberlite perovskite U-Pb dating Sr isotopes Nd isotopes Kuruman Kaapvaal Craton |
| ISSN号 | 0022-3530 |
| DOI | 10.1093/petrology/egs057 |
| 文献子类 | Article |
| 英文摘要 | The Kuruman Kimberlite Province contains the oldest known kimberlites in the Kaapvaal Craton (similar to 1 center dot 6-1 center dot 8 Ga), but only limited geochronological and isotopic data exist for this province. To provide better constraints on the sources of the kimberlite magmas and the timing of magmatism, we have carried out in situ U-Pb dating and Sr-Nd isotopic analysis of groundmass perovskite from four of the Kuruman kimberlites (Bathlaros, Elston, Helpmekaar and Zero). We also have measured the Sr-isotope composition of groundmass apatite and carbonate in several of the kimberlites, for comparison with published whole-rock isotopic data. Attempts to date perovskite using in situ laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) were hindered by extensive Pb loss, even in apparently unaltered grains, yielding anomalously young emplacement ages. The assumption of a Mesoproterozoic common-Pb component allows the extraction of intercept ages from the least altered grains (Bathlaros, 1640 +/- 13 Ma; Elston, 1663 +/- 49 Ma; Helpmekaar, 1638 Ma; Zero, 1845 +/- 45 Ma). The smaller sampling volume of secondary ion mass spectrometry and the ability to measure Pb-204, thus allowing more precise common-Pb corrections, produces concordant ages. These reveal that kimberlite intrusion occurred over a time span of similar to 200 Myr (Bathlaros, 1647 +/- 27 Ma; Zero, 1835 +/- 25 Ma), with emplacement ages younging to the east. The results of this study suggest that alteration may disrupt the U-Pb system in perovskite. In situ Sr and Nd isotope analyses [LA-multi-collector (MC)-ICP-MS] of perovskite show a moderate range in values (Sr-87/Sr-86((i)) = 0 center dot 70383-0 center dot 70507; epsilon Nd-(i) = -2 center dot 7 to 1 center dot 5), but similar mean values among the four kimberlites (Sr-87/Sr-86((i)) = 0 center dot 70396-0 center dot 70425; epsilon Nd-(i) = -0 center dot 8 to 0 center dot 8). The Nd-isotope compositions of perovskite are similar to those of whole-rock samples of the host kimberlite (epsilon Nd-(i) = 1 center dot 0 to -3 center dot 0), whereas Sr in perovskite and apatite (Sr-87/Sr-86((i)) = 0 center dot 70424-0 center dot 70427) is more radiogenic than the whole-rock values (Sr-87/Sr-86((i)) = 0 center dot 70293-0 center dot 70382). However, groundmass carbonates generally yield lower values (Sr-87/Sr-86((i)) = 0 center dot 70348-0 center dot 70405), closer to those of the kimberlite samples, indicating that the whole-rock Sr isotope compositions are largely controlled by carbonates, probably assimilated from the immediate country rocks. The isotopic data suggest that the Kuruman kimberlite magmas were initially derived from a deeper sub-lithospheric source region, but their distinctive compositional characteristics were imposed through assimilation, first of metasomatized sub-continental lithospheric mantle and later of crustal material, during magma ascent. |
| WOS关键词 | MC-ICP-MS ; PLASMA-MASS SPECTROMETRY ; TRACE-ELEMENT COMPOSITION ; RARE-EARTH ELEMENTS ; LITHOSPHERIC MANTLE ; SOMERSET ISLAND ; DHARWAR-CRATON ; OFF-CRATON ; SUBCONTINENTAL MANTLE ; GROUNDMASS PEROVSKITE |
| WOS研究方向 | Geochemistry & Geophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:000311670500004 |
| 出版者 | OXFORD UNIV PRESS |
| 资助机构 | DEST ; DEST ; ARC LIEF ; ARC LIEF ; NCRIS ; NCRIS ; Macquarie University ; Macquarie University ; SIMS(Cameca1280) ; SIMS(Cameca1280) ; State Key Laboratory of Lithospheric Evolution ; State Key Laboratory of Lithospheric Evolution ; ARC ; ARC ; DEST ; DEST ; ARC LIEF ; ARC LIEF ; NCRIS ; NCRIS ; Macquarie University ; Macquarie University ; SIMS(Cameca1280) ; SIMS(Cameca1280) ; State Key Laboratory of Lithospheric Evolution ; State Key Laboratory of Lithospheric Evolution ; ARC ; ARC ; DEST ; DEST ; ARC LIEF ; ARC LIEF ; NCRIS ; NCRIS ; Macquarie University ; Macquarie University ; SIMS(Cameca1280) ; SIMS(Cameca1280) ; State Key Laboratory of Lithospheric Evolution ; State Key Laboratory of Lithospheric Evolution ; ARC ; ARC ; DEST ; DEST ; ARC LIEF ; ARC LIEF ; NCRIS ; NCRIS ; Macquarie University ; Macquarie University ; SIMS(Cameca1280) ; SIMS(Cameca1280) ; State Key Laboratory of Lithospheric Evolution ; State Key Laboratory of Lithospheric Evolution ; ARC ; ARC |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/84096]  |
| 专题 | 中国科学院地质与地球物理研究所 |
| 通讯作者 | Griffin, William L. |
| 作者单位 | 1.Macquarie Univ, Dept Earth & Planetary Sci, Australian Res Council, Ctr Excellence Core Crust Fluid Syst GEMOC, Sydney, NSW 2109, Australia 2.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China |
| 推荐引用方式 GB/T 7714 | Donnelly, Cara L.,Griffin, William L.,Yang, Jin-Hui,et al. In situ U-Pb Dating and Sr-Nd Isotopic Analysis of Perovskite: Constraints on the Age and Petrogenesis of the Kuruman Kimberlite Province, Kaapvaal Craton, South Africa[J]. JOURNAL OF PETROLOGY,2012,53(12):2497-2522. |
| APA | Donnelly, Cara L..,Griffin, William L..,Yang, Jin-Hui.,O'Reilly, Suzanne Y..,Li, Qiu-Li.,...&Li, Xian-Hua.(2012).In situ U-Pb Dating and Sr-Nd Isotopic Analysis of Perovskite: Constraints on the Age and Petrogenesis of the Kuruman Kimberlite Province, Kaapvaal Craton, South Africa.JOURNAL OF PETROLOGY,53(12),2497-2522. |
| MLA | Donnelly, Cara L.,et al."In situ U-Pb Dating and Sr-Nd Isotopic Analysis of Perovskite: Constraints on the Age and Petrogenesis of the Kuruman Kimberlite Province, Kaapvaal Craton, South Africa".JOURNAL OF PETROLOGY 53.12(2012):2497-2522. |
入库方式： OAI收割
来源：地质与地球物理研究所
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