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

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。

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 lithosphereasthenosphere 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. mineralizationconcentrated 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.