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中国东部中生代软流圈上涌与构造-岩浆-矿集区
Mesozoic asthenosphere upwelling of Eastern China and its effects on structure-magma-mineralization-concentrated region
【摘要】 在深入研究华南地震层析成像的基础上,按照大地构造环境和软流圈上涌形状和热度,将中国东部(大陆)中生代上地幔中岩石圈-软流圈构造划分为3类:(1)陆台区(华北块和扬子块),软流圈沿古裂陷上涌,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,并于软流圈与岩石圈厚区之陡接触带形成中基性杂岩及相应Fe矿集区;(2)褶皱带中心区(南岭及其延伸带),软流圈在适当深度、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;(3)褶皱带边缘区(大兴安岭南部及华南南缘),在软流圈上涌柱上方形成幔源或幔壳混熔的花岗质岩,相应为Cu、Au、Pb-Zn、Mo、Ag矿集区。总之,软流圈上涌是中生代构造、岩浆、矿集区形成之根源。
【Abstract】 Based on the detailed study of seismic tomography image in South China,and according to the geotectonic environment and shape and heat of asthenosphere upwelling,we divided the structure of lithosphere-asthenosphere at the Mesozoic upper mantle of Eastern China into three types.(1)Continental platform area(North China platform and Yangtze platform):asthenosphere upwelled along paleo-rift;over the plume head,the granitic rocks of crust and mantle mixed and correspondingly,Au,Cu,Mo,Pb-Zn,etc.mineralization-concentrated regions were formed;and at the steep contact belt of asthenosphere and the thick area of lithosphere,mediate-basic complex was formed.(2)Central area of fold zone(Nanling and its extension zone):asthenosphere was "recumbent" at suitable depth,with adequate heat and in a great extent;by heat conduction,the interior of partial crust remelted,and the crust-source granitic rocks,and correspondingly,W,Sn and rare elements mineralization-concentrated regions were formed.(3)Marginal area of fold zone(Southern Daxinganling and southern margin of South China):the mantle-source or crust-mantle mixed granitic rocks,and correspondingly,Cu,Au,Pb-Zn,Mo,Ag mineralization-concentrated regions were formed.In conclusion,asthenosphere upwelling is the origin of the formation of Mesozoic structures,magma,and mineralization-concentrated regions.
【Key words】 geotectonic environment; asthenosphere upwelling; asthenosphere recumbent; plume body and head; mineralization-concentrated region;
- 【文献出处】 地学前缘 ,Earth Science Frontiers , 编辑部邮箱 ,2009年04期
- 【分类号】P546
- 【被引频次】12
- 【下载频次】405