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| 基金项目：国家自然科学基金青年科学基金项目（41402075） |
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| 摘要： |
| 在江苏北部寻找金刚石原生矿的过程中，于徐州北部西村发现18条苦橄玢岩脉（管）。研究发现，在岩石地球化学方面，该区苦橄玢岩与山东、辽宁等地区的金伯利岩具有相似性：二者均属偏碱性超基性岩，徐州西村苦橄玢岩以MgO含量低，Al2O3、CaO、K2O含量偏高，w(Fe3+)/w(Fe2+)比＞1为特征，与碳酸盐化金伯利岩的地球化学特征相似；二者的过渡族金属元素球粒陨石标准化配分曲线均为“M”型，且以显著的Ti、Nb正异常及陡倾斜为特征，稀土元素球粒陨石标准化配分曲线均显示轻稀土相对富集、重稀土相对亏损；辽宁、山东地区金伯利岩富集Nb，Nb与Cr、Ni、Co等呈正相关，而徐州西村苦橄玢岩中的Nb则与Cr、Ni、Co等呈负相关。这些地球化学特征说明，徐州西村苦橄玢岩与辽宁、山东地区的金伯利岩具有一定的成因联系，为该区金刚石找矿提供了有利线索。 |
| 关键词：苦橄玢岩 金伯利岩 岩石学特征 江苏徐州 |
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| Abstract: |
| In prospecting primary diamond deposits, we discovered 18 picrite-porphyrite dykes in Xicun Village, north of Xuzhou. Xicun picrite-porphyrite shares many geochemical similarities with the kimberlite in Shandong and Liaoning provinces. These rocks are all alkali ultra-basic rocks and Xicun picrite porphyrite has similar chemical compositions (low w(MgO); high w(Al2O3), w(CaO), w(K2O), w(Fe3+)/w(Fe2+) > 1) with carbonatite kimberlites. Their chondrite-normalized distribution curves of transition metal elements are M-shape and display significant positive anomalies of Ti and Nb and sharp dip. Chondrite-normalized REE distribution patterns display strong enrichment of LREE and relative depletion of HREE. The kimberlites in Shandong and Liaoning are characterized by enrichment of Nb and show positive correlation of Nb with Cr, Ni and Co, whereas the picrite-porphyrite in Xicun have low Nb content and show negative correlation of Nb with Cr, Ni and Co. These geochemical characteristics indicate a likely genetic relationship between the picrite-porphyrite and kimberlites, which has significance for prospecting of diamond. |
| Keywords:picrite-porphyrite kimberlite petrologic characteristic Xuzhou City in Jiangsu |
| 施建斌，蔡逸涛，张琪，等.徐州北部西村苦橄玢岩地球化学特征及其与金伯利岩的对比[J].地质学刊,2017,41(4):535-541 |
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