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首页> 外文期刊>Contributions to Mineralogy and Petrology >The Kimberlites and related rocks of the Kuruman Kimberlite Province, Kaapvaal Craton, South Africa
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The Kimberlites and related rocks of the Kuruman Kimberlite Province, Kaapvaal Craton, South Africa

机译：南非Kaapvaal Craton库鲁曼·金伯利岩省的金伯利岩及相关岩石

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The Kuruman Kimberlite Province is comprised of 16 small pipes and dikes and contains some of the oldest known kimberlites (>1.6 Ga). In this study, 12 intrusions are subdivided into three groups with distinct petrology, age, and geochemical and isotopic compositions: (1) kimberlites with groundmass perovskites defining a Pb–Pb isochron age of 1787 ± 69 Ma, (2) orangeite with a U–Pb perovskite age of 124 ± 16 Ma, and (3) ultramafic lamprophyres (aillikite and mela-aillikite) with a zircon U–Pb age of 1642 ± 46 Ma. The magma type varies across the Province, with kimberlites in the east, lamprophyres in the west and orangeite and ultramafic lamprophyres to the south. Differences in the age and petrogenesis of the X007 orangeite and Clarksdale and Aalwynkop aillikites suggest that these intrusions are probably unrelated to the Kuruman Province. Kimberlite and orangeite whole-rock major and trace element compositions are similar to other South African localities. Compositionally, the aillikites typically lie off kimberlite and orangeite trends. Groundmass mineral chemistry of the kimberlites has some features more typical of orangeites. Kimberlite whole-rock Sr and Nd isotopes show zoning across the Province. When the kimberlites erupted at ~1.8 Ga, they sampled a core volume (ca 50 km across) of relatively depleted SCLM that was partially surrounded by a rim of more metasomatized mantle. This zonation may have been related to the development of the adjacent Kheis Belt (oldest rocks ~2.0 Ga), as weaker zones surrounding the more resistant core section of SCLM were more extensively metasomatized.
机译：库鲁曼·金伯利特省由16条小烟斗和堤坝组成，并包含一些已知的最古老的金伯利岩（> 1.6 Ga）。在这项研究中，将12个侵入岩分为三类，分别具有不同的岩石学，年龄，地球化学和同位素组成：（1）钙钛矿的基体钙钛矿定义的Pb–Pb等时年龄为1787±69 Ma，（2）铀的U岩–钙钛矿的年龄为124±16 Ma，（3）锆石U–Pb年龄为超镁铁煌斑（硅铝石和黑云母），年龄为1642±46 Ma。整个省的岩浆类型各不相同，东部为金伯利岩，西部为煌斑岩，南部为橘红岩和超镁铁岩煌斑岩。 X007橘岩矿和克拉克斯代尔矿和Aalwynkop硅藻土的年龄和成岩作用的差异表明，这些入侵可能与库鲁曼省无关。金伯利岩和橙岩全岩主岩和微量元素的组成与其他南非地区相似。从成分上讲，aillikites通常摆脱了金伯利岩和橘子岩的趋势。金伯利岩的地面质量矿物化学具有一些橘红色岩所特有的特征。金伯利岩全岩的Sr和Nd同位素在全省范围内显示分区。当金伯利岩在〜1.8 Ga处爆发时，他们取样了一个相对枯竭的SCLM的岩心体积（横跨50 km），该岩心部分被更多交化的地幔边缘所包围。该分区带可能与相邻的Kheis带（最古老的岩石〜2.0 Ga）的发育有关，因为围绕SCLM更具抵抗力的岩心部分的较弱区域被广泛地交代。

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