| 华北克拉通后太古宙碎屑沉积岩地球化学研究——三叠纪的成分变化及其意义 |
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| 引用本文： | 贾望鲁,高山.华北克拉通后太古宙碎屑沉积岩地球化学研究——三叠纪的成分变化及其意义[J].地球科学,1999,24(2). |
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| 作者姓名： | 贾望鲁 高山 |
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| 作者单位： | 中国地质大学地球科学学院 |
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| 基金项目： | 国家自然科学基金,国家教委基金,国土资源部壳幔体系组成、物质交换及动力学开放实验室基金 |
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| 摘 要： | 通过３０个组合样品的分析，研究了华北克拉通古元古代到第三纪的碎屑沉积岩地球化学变化．结果表明，华北克拉通后太古宙沉积岩组成并不均一．元古宙沉积岩组成变化范围较大，元古宙以后的沉积岩Ｅｕ／Ｅｕ，ｗ（Ｃｒ）／ｗ（Ｔｈ），ｗ（Ｓｃ）／ｗ（Ｔｈ）和ｗ（Ｓｍ）／ｗ（Ｎｄ）等元素质量分数比值较低，具有后太古宙沉积岩的典型特征．三叠纪泥质岩的上述元素比值明显增大，相容元素质量分数很高，表明其源区有较多镁铁质组分加入．作者将这一变化归因于三叠纪华北克拉通和扬子克拉通发生的陆－陆碰撞作用．碰撞过程中秦岭－大别造山带深部地壳的镁铁—超镁铁岩大量出露，随后被剥蚀、搬运至华北克拉通的沉积盆地内．
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| 关 键 词： | 三叠纪 成分变化 陆-陆碰撞 后太古宙 碎屑沉积岩 地球化学 华北克拉通 |
GEOCHEMICAL STUDY OF POST-ARCHAEAN CLASTIC SEDIMENTARY ROCKS OF NORTH CHINA CRATON--COMPOSITIONAL CHANGE IN TRIASSIC SEDIMENTS AND ITS IMPLICATIONS |
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| Jia Wanglu,Gao Shan.GEOCHEMICAL STUDY OF POST-ARCHAEAN CLASTIC SEDIMENTARY ROCKS OF NORTH CHINA CRATON--COMPOSITIONAL CHANGE IN TRIASSIC SEDIMENTS AND ITS IMPLICATIONS[J].Earth Science-Journal of China University of Geosciences,1999,24(2). |
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| Authors: | Jia Wanglu Gao Shan |
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| Abstract: | Geochemical variations of Proterozoic to Tertiary clastic sedimentary rocks are studied by analysis of thirty composite samples from the North China craton (NCC). The results indicate that the composition of post_Archaean sedimentary rocks of NCC is not uniform. Proterozoic sediments show larger geochemical compositional variations than those of other ages. The Phanerozoic sedimentary rocks are characterized by relatively lower Eu/Eu *, w (Cr)/ w (Th), w (Sc)/ w (Th) and w (Sm)/ w (Nd) ratios typical of post_Archaean sedimentary rocks worldwide. However, Triassic pelite exhibits a significant increase in these ratios and in the mass fractions of some compatible elements, indicating that increasing addition of ferromagnesian components in its provenance. This change is attributed to the Triassic collision between NCC and the Yangtze craton. This collision led to exhumation of mafic-ultramafic rocks in the deep crust of the Qinling_Dabie orogeneic belt, which were subsequently eroded and deposited in NCC basins. |
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| Keywords: | Triassic compositional change continent_continent collision post_Archaean clastic sedimentary rocks geochemistry North China craton |
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