地质学报（英文版）2004，Vol.78Issue(1)：203-220,18.
Large-scale Migration of Fluids toward Foreland Basins during Collisional Orogeny:Evidence from Triassic Anhydrock Sequences and Regional Alteration in the Middle-Lower Yangtze Area
Large-scale Migration of Fluids toward Foreland Basins during Collisional Orogeny:Evidence from Triassic Anhydrock Sequences and Regional Alteration in the Middle-Lower Yangtze Area
HOU Zengqian 1YANG Zhusen 1LI Yinqing 1ZENG Pusheng 1MENG Yifeng1
作者信息
- 1. Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037
- 折叠
摘要
Abstract
The middle-lower Yangtze area underwent a series of complex tectonic evolution, such as Hercynian extensional rifting, Indosinian foreland basining, and Yanshanian transpression-transtension, resulting in a large distinctive Cu-Fe-Au metallogenic belt. In the tectonic evolution, large-scale migration and convergence of fluids toward foreland basins induced during the collisional orogeny of the Yangtze and North China continental blocks were of vital importance for the formation of the metallogenic belt. Through geological surveys of the middle-lower Yangtze area,three lines of evidence of large-scale fluid migration are proposed: (1) The extensive dolomitic and silicic alteration penetrating Cambrian-Triassic strata generally occurs in a region sandwiched between the metallogenic belt along the Yangtze River and the Dabie orogenic belt, and in the alteration domain alternately strong and weak alteration zones extend in a NW direction and are controlled by the fault system of the Dabie orogenic belt; it might record the locus of the activities of long-distance migrating fluids. (2) The textures and structures of very thick Middle-Lower Triassic anhydrock sequences in restricted basins along the river reveal the important contribution of the convergence of regional hot brine in restricted basins and the chemical deposition or their formation. (3) Early-Middle Triassic syndepositional iron carbonate sequences and Fe-Cu-Pb-Zn massive sulfide deposits alternate with anhydrock sequences or are separated from the latter, but all of them occur in the same stratigraphic horizon and are intimately associated with each other,being the product of syndeposition of high-salinity hot brine. According to the geological surveys, combined with previous data, the authors propose a conceptual model of fluid migration-convergence and mineralization during the Dabie collisional orogeny.关键词
large-scale migration of fluids/collisional orogeny/anhydrock sequence/regional alteration/middle-lower Yangtze RiverKey words
large-scale migration of fluids/collisional orogeny/anhydrock sequence/regional alteration/middle-lower Yangtze River引用本文复制引用
HOU Zengqian,YANG Zhusen,LI Yinqing,ZENG Pusheng,MENG Yifeng..Large-scale Migration of Fluids toward Foreland Basins during Collisional Orogeny:Evidence from Triassic Anhydrock Sequences and Regional Alteration in the Middle-Lower Yangtze Area[J].地质学报（英文版）,2004,78(1):203-220,18.
