川滇黔菱形地块地球物理基本特征及其与内生成矿作用的关系  

Basic Geophysic Characteristics of Sichuan-Yunnan-Guizhou Rhombic Block and its Relationship with Endo-mineralization

作　　者：王宝禄 李丽辉 曾普胜[2] 

机构地区：[1]云南省地质调查院,云南昆明650011 [2]中国地质科学院矿产资源研究所,北京100037

出　　处：《东华理工学院学报》2004年第4期301-308,共8页Journal of East China Institute of Technology

基　　金：国土资源部重点成矿物探化探遥感编图成果综合研究矿产预测项目 (地直发 [1 991 ] 0 94号 ) ;国家自然科学基金项目(40 2 72 0 4 6)

摘　　要：扬子准地台西南缘是我国重要的成矿区带。通过该区区域地球物理资料 (包括重力测量、航空磁测、深反射地震和天然地震资料 )的分析整理和编图 ,发现在扬子地台西南缘存在着一个菱形块体———川滇黔菱形地块 ,由四条 (隐伏 )深断裂带所围限。地球物理资料较为清楚地反映了菱形地块的构造格架。西侧重力异常梯度陡变 ,地壳厚度急剧变厚 ;内部存在由地幔隆起形成的重力高异常带 ,隆起带可能是菱形地块在元古宙时期裂解留下的遗迹 ;沿边界断裂地震活动剧烈而频繁。菱形块体的边界断裂及其内部的隆起带控制着本区的成矿作用 ,不同时期的矿产在菱形地块内有规律地分布 ,沿近南北向地幔隆起带分布有元古代沉积 喷流型Fe Cu矿床 ,其两侧分布有与晚古生代峨眉山玄武岩有关的铜矿和密西西比型铅锌矿床 ;沿菱形块体边界分布有新生代与超壳深断裂有关的富碱斑岩型金 (多金属 )矿床 ,沿菱形地块内部的南北向深断裂 (如小江深断裂 )有剪切带型金矿床。不同类型的矿床有时相互叠加形成复合成因的矿床 (如东川地区 )。这表明 ,不同时期的构造背景控制着不同类型矿床 ,同时表明 ,扬子地台西南缘是一个不够稳定的地块 (准地台或活化了的地台 ) ,菱形地块陡变的地球物理特征明显不同于其东侧稳定块体 (缓变 )The western rim of the Yangzi Paraplatform, is one of the most important metallogenic belts in the Southwest of China. By the result of data-processing and compiling of geophysics, including regional gravity survey, aeromagnetic survey, deep reflect imagine of seismic and natural seismic, it is discovered that there exists a rhombic block, Chuan-Dian-Qian Rhombic Block(Chuan, Dian and Qian is the short name of Sichuan, Yunnan and GuiZhou, respectively), which is surrounded by four faults in various directions. The information of geophysics reveals clearly the tectonic framework of the rhombic block. At the western of rhombic block, the gradient of gravity anomaly changes sharply, showing crust soundly thickening westwards, within the rhombic block there exists an positive gravity anomaly zone caused by mantle′s doming striking SN direction, which should be a relict of early stage (Proterozoic) rift inside rhombic block; along the boundary of the rhombic block seismic activities have frequently been taken place. The boundary faults of rhombic block, as well as the rise belt within the block, control the metallogeny in this region. Ore deposits, produced in varying geological time, are distributed regularly in the rhombic block: along the SN mantle rise zone of the rhombic block′s center, Proterozoic VMS-type Fe-Cu ore deposits; Cu deposits and MVT Pb-Zn deposits, related to Late Paleozoic (Permian) Emeishan basalt, are distributed in the two flanks; along the boundary faults of the rhombic block, porphyry Au deposits related to alkalic porphyries are occurred; along the deep faults inside the block(such as Xiaojing Deep Fault), shear zone-type Au deposits are produced. In some occasion, deposits with different types are superposed to form composite genesis deposits, such as in Dongchuan district. The result shows that the tectonic setting in different stage controls deposits of different types, at the same time, the west rim of Yangtze Paraplatform is not steady enough(rejuvenated at Paleozoic to Cenozoic), wi

关 键 词：地球物理 隆起带 矿床 边界断裂 内生成矿作用 地幔 扬子地台 内部 西南 地块 

分 类 号：N02[自然科学总论—科学技术哲学] P618[天文地球—矿床学]