| 华北克拉通-扬子克拉通与秦岭造山带古地幔组成及状态的对比 |
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| 引用本文： | 路凤香,郑建平,王方正,孙平,刘永顺,赵磊.华北克拉通-扬子克拉通与秦岭造山带古地幔组成及状态的对比[J].地球科学,1997,6(3). |
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| 作者姓名： | 路凤香 郑建平 王方正 孙平 刘永顺 赵磊 |
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| 作者单位： | 地球科学学院，地质矿产系 |
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| 摘 要： | 经研究，华北克拉通古地幔以含石榴石的二辉橄榄岩、方辉橄榄岩及纯橄榄岩为主．地幔交代作用强烈，岩石富集不相容元素，明显高于南非及西澳克拉通者．扬子克拉通古地幔主元素亏损程度差，交代作用较弱，岩石为石榴石／尖晶石二辉橄榄岩．秦岭造山带壳、幔交界带的岩石类型复杂，包括蛇纹石化尖晶石二辉橄榄岩（蛇纹岩）、石榴石辉石岩、榴闪岩、变辉长岩及变玄武岩等．蛇纹岩遭受强的塑性流变，剪切变形结构发育．与克拉通相比，地幔交代作用很弱．３个地幔域的古地温状态有差异，秦岭造山带最高，扬子克拉通居中，华北克拉通最低．上述结果表明，两克拉通的古地幔特征相差显著，暗示经历了不同的演化过程．交代作用可能发生在１７００Ｍａ以前和１１００～５００Ｍａ，后者强于前者．造山带地幔的剪切变形明显强于克拉通地幔
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| 关 键 词： | 古地幔，地幔交代作用，古地温状态 |
THE COMPARISON OF CONSTITUTION AND THERMAL CONDITION IN NORTH CHINA CRATON (NC), YANGTZE CRATON (YZ) AND QINLING (QL) OROGENIC BELT |
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| Lu Fengxiang,Zheng Jianping,Wang Fangzhen,Sun Ping.THE COMPARISON OF CONSTITUTION AND THERMAL CONDITION IN NORTH CHINA CRATON (NC), YANGTZE CRATON (YZ) AND QINLING (QL) OROGENIC BELT[J].Earth Science-Journal of China University of Geosciences,1997,6(3). |
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| Authors: | Lu Fengxiang Zheng Jianping Wang Fangzhen Sun Ping |
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| Abstract: | The main rock types of Paleozoic lithospheric mantle in NC are garnet lherzolites, harzburgites, and dunites. All samples have high ICE (incompatible element) and REE contents showing very strong mantle metasomatism. The normalized La values are higher than those in Kappvaal craton and west Australia craton. The major elements of lithospheric mantle in YZ are more fertile than those in NC and the main rock type is garnet lherzolite. The normalized La values show the less enrichment feature of lithospheric mantle in YZ. The rock types in QL belt are more complicated, including serpintinized spinel lherzolite (serpentite), garnet pyroxinite, eclogitic garnet amphibolites, metagabbro and meta basalt. The serpentites show stronger shear deformation and no or less mantle metasomatism than that of the samples in craton. The palaeo geotherms are different between three areas, the highest one in the QL, YZ in the middle, and NC, the lowest. According to these data, the characteristics varied remarkably between two cratons implying the different geological evolution between them. The metasomatism may occur in two periods, 1700Ma and from 1100Ma to 500Ma and the latter was stronger than the former. The mantle deformation in orogenic belt was stronger than that in craton. |
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| Keywords: | Palaeo mantle mantle metasomatism Palaeo geotherm condition |
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