机构地区:[1]山西省地质勘查局地球物理化学勘查院,山西运城044004 [2]中国地质大学地球科学学院,湖北武汉430074 [3]中国科学院地质与地球物理研究所,北京100029
出 处:《地球科学》2019年第5期1570-1583,共14页Earth Science
基 金:中国地质调查局项目(Nos.1212010733802;12120113012500;1212011220529)
摘 要:以深部地球物理资料为基础,结合大地构造环境、岩浆岩同位素示踪及矿产资源分布规律,加以综合分析.通过热力学计算可知,中国东部近2亿年来的上地幔岩石圈/软流圈构造可以存留至今,且能区分出中、新生代.软流圈上涌与矿集区:(1)中生代金属矿:(a)克拉通区,软流圈沿柱身上涌,其柱头上方形成幔壳混熔花岗质岩及相应Au、Cu、Mo、Pb-Zn等矿集区,并于柱身与岩石圈块体陡接触带,形成中基性杂岩及相应富Fe矿集区;(b)褶皱带区,在软流圈上涌柱上方形成近幔源型花岗质岩,相应为Cu、Au、Pb-Zn、Mo、Ag矿集区;(c)南岭带,软流圈层在适当深度、热量充足、较大范围内"平卧",因热传导而致使地壳内物质部分重熔,形成壳源型花岗质岩及相应的W、Sn、稀有元素矿集区;(2)新生代油气田:(a)与太平洋板块俯冲有关的软流圈上涌,其上方出露玄武岩,形成较大型油田;(b)与裂陷盆地有关的软流圈上涌,其上方形成大型油田,也有中小型油田.软流圈上涌与大地构造:中生代J-K时期,通过构造力特征等的综合分析,阐明燕山运动的根源及其影响;新生代侧重剖析大陆裂谷相关特征.总之,软流圈上涌是岩石圈减薄,以及中、新生代构造-岩浆-矿集区形成的根源.Based on the deep geophysical data, a comprehensive study is carried out by analyzing the tectonic environment, magma isotopic tracing and laws of distribution of mineral resources. The thermodynamic calculation indicates that the structure of the upper mantle lithosphere and asthenosphere of the eastern China which is near 200 Ma can be kept to now, and the time of Mesozoic and Cenozoic can be recognized. Results show the following asthenosphere upwelling and mineralization concentration regions.(1) Mesozoic metal deposit:(a) Craton area, asthenosphere upwelled along the plume body, above the plume head, there formed intermingling granitic rock of crust and mantle melts and corresponding Au, Cu, Mo, Pb-Zn etc mineralization concentrated region. And in the steep contact belt of the plume body and lithosphere body, there formed mediate-basic complex and corresponding Fe mineralization concentrated region.(b) Fold belt area, above the asthenosphere upwelling plume, there formed near mantle-source granitic rocks, and corresponding Cu, Au, Pb-Zn, Mo, Ag mineralization concentrated region.(c) Nanling belt, asthenosphere was "recumbent" at suitable depth, with adequate heat and to a great extent, for heat conduction, the interior of crust remelted partially, and the crust-source granitic rocks, corresponding W, Sn and rare elements mineralization concentrated regions were formed.(2) Cenozoic oil and gas field:(a) Asthenosphere upwelling related with the Pacific subduction, above them, there outcropped basalt, and formed large-scale oil field.(b) Asthenosphere upwelling related with the rift basin, above them, there formed large-scale oil fields, also medium- and small-scale oil fields. Asthenosphere upwelling and tectonic:at J-K of Mesozoic, through comprehensive analysis of tectonic force etc, the origin and influence of Yanshan movement are presented. For Cenozoic, the characters related with continental rift should be analyzed essentially. In conclusion, asthenosphere upwelling is the origin of lithosphere thinning
关 键 词:深部构造 软流圈上涌 软流圈平卧 柱身和柱头 金属矿集区 构造造山 构造地质
分 类 号:P31[天文地球—固体地球物理学]
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