贺兰山深部构造及其对浅部构造的响应过程  

DEEP-SEATED STRUCTURES AND THEIR RESPONSE TO CRUSTAL STRUCTURES IN THE HELANSHAN AREA

作　　者：白斌[1] 周立发[1] 张义楷[1] 刘哲[2] 杨文敬[2] 刘新社[3] 章贵松[3] 

机构地区：[1]大陆动力学国家重点实验室西北大学地质系,陕西西安710069 [2]长庆油田分公司勘探部,陕西西安710021 [3]长庆油田分公司研究院,陕西西安710021

出　　处：《大地构造与成矿学》2008年第1期42-49,共8页Geotectonica et Metallogenia

基　　金：国家重点基础研究发展项目(973项目)(编号2003CB214601、2002CCC01400)资助

摘　　要：根椐实测贺兰山地区二叠系、三叠系和侏罗系含煤地层热解数据及石英脉中包裹体测温发现贺兰山地区热演化程度整体水平较高，相对邻区而言，明显具有异常地热场的特征。在分析航磁△T化极图、重力上延5km、10km等值线图后认为该区并不存在磁力高，前人设想贺兰山下2-5km处发育中酸性巨型岩基造成该区地热异常的说法缺乏足够证据。并且在贺兰山地区重力上延3km、5km等值线图上存在明显的重力高，剩余重力异常、莫霍面深度和地温梯度图也显示贺兰山地区为一热异常的幔隆区，它明显有别于其他造山带区。因此，贺兰山地区的高热演化特征应是莫霍面的上隆引起的地温梯度升高所致。最后结合研究区玄武岩地质地球化学特征认为贺兰山及周邻地区莫霍面上隆是造成早中侏罗世以来的热事件的原因。Based on the pyrolytic data from coal layers and the inclusion thermometric data from the quartz veins of the Permian, Triassic and Jurassic in the Helanshan Mountains, it is shown that there is a high thermal evolution level in the Helanshan area, which indicates a characteristic of geothermal anomalous field. The aeromagnetic polarization and contour diagrams for aeromagnetic survey with upward extension to 5km and 10km show that the He- lanshan Mountains has no magnetic anomaly, and thus, the former assumption that there is an intermediate acidity rock beneath the Helanshan Mountains causing the high geothermal anomaly lacks sufficient evidences. Gravity maps with upward extension to 3km and 5km obviously show positive anomalies. The residual gravity anomaly, Mo-ho depth and geothermic gradient diagrams all show that there is a mantle uplifted area in the Helanshan area, which is obviously different from other orogenic belts. The high thermal evolutional characteristic in the Helanshan area could be an indicative of the high geothermal level from the Moho uplift. Combining the basaltic geochemical behavior, we conclude that the Moho uplift in the Helanshan and its adjecent areas may be the result of a thermal event since the Middle Jurassic.

关 键 词：鄂尔多斯西缘 深部构造 浅部构造 

分 类 号：P542[天文地球—构造地质学]