湘南骑田岭矿集区的深部构造特征及其对区域成矿的制约  

The Deep Tectonic Features of Qitianling Ore-Concentrated Area in Southern Hunan Province and Its Contrains to the Regional Ore-Forming Processes

作　　者：李建国[1] 李建康[2] 王登红[2] 刘健[1] 何晗唅 

机构地区：[1]山西省地球物理化学勘查院,山西运城044004 [2]中国地质科学院矿产资源研究所,北京100037

出　　处：《地质学报》2014年第4期695-703,共9页Acta Geologica Sinica

基　　金：国家深部探测专项"南岭成矿带地壳岩浆系统结构探测实验研究"(SinoProbe-03-01);地质大调查项目"我国稀有;稀散资源战略调查研究"(1212011220805)资助成果

摘　　要：湘南骑田岭矿集区是我国重要的有色金属基地之一，具有断裂构造异常发育，存在多期次岩浆活动、多类型矿床和矿种组合的特点。为了揭示深部地壳结构对区域成矿特征的制约，本文布置了穿越黄沙坪铅锌矿床和骑田岭花岗岩体的人工地震剖面，数据采集采用了直线多次叠加的技术方法，采取大炮和小炮相结合的激发方式进行实验工作，共完成物理点651个。实验结果表明，骑田岭矿集区深、中、浅部存在着比较明显的地震构造波组，莫霍面深度约为33～38km；在骑田岭岩体深部存在明显的莫霍面不连续性，呈现出类似于“逆断层”的构造特征和无反射波组或弱波组异常；反射速度反演结果也表明骑田岭岩体深部存在着下凹状低速度异常。这些深部构造特征说明区域存在幔源物质上涌和参与成岩成矿作用的通道，该构造通道可对应于茶陵-郴州-临武深大断裂带，暗示地幔物质的混入可能是湘南骑田岭矿集区发生大规模成矿作用的内在原因之一。而且，莫霍面“逆断层”构造特征显示区域上曾遭受较强烈的构造挤压作用，是区域中生代多次构造挤压作用的体现。这种构造挤压作用致使岩石圈增厚，发生较大规模的拆沉作用和深部岩浆上侵活动，为区域成矿作用提供必要的物质和能量。The Qitianling ore-contrated area in Southern Hunan province,one of the most important nonferrous metal bases in China with extensive fault structure,sufured multiperiod magmatic activity such as the intrusion of Qitianling granite,and produced many types of ore deposits with multi-mineral such as Huangshaping Pb-Zn deposit.In order to analyze the contrains of deep tectonic features to the ore-forming processes in Qitianling area,an artificial seismic profile crossing the Huangshaping deposit and Qitianling granite body was finished.The seismic data collected from 651 physical points was stacked linearly,and the artifical earthquake was excitated through big shots combining with small shots.The reflection seismic profile showed that three obvious wave groups were existed in the upper,middle and deep part of Qitianling area,and Moho locates at the depth of 33~38 km.In the depth of the Qitianling granitic intrusion,the seismic wave groups reflect that Moho is not continuous in the tectonic style of reverse fault and funnel,which is consistent with the distribution shape of seismic wave velocity.These features illustrated the exitence of an upwelling pathway for mantle material,which possible ascribed to the intrusion of granitic magma and the regional mineralization.The pathway can correspond to the Chaling-Chenzhou-Linwu deep faults,indicating that the participation of mantle material was one of the key factors for the large-scale mineralization in Qitianling area.The features of Moho suggested that strong squeezing action ever occurred in Mesozoic in Qitianling area,finally leading to the thickning of lithospheric mantle, and then the delamination and magma intrusion.In such process,mineralization material and energy were provided.

关 键 词：反射地震剖面 地壳结构 湘南骑田岭矿集区 黄沙坪 南岭成矿带 

分 类 号：P613[天文地球—矿床学]