郯庐断裂带晚第三纪以来的浅部挤压活动与深部过程  

POST-EOGENE COMPRESSIVE ACTIVITIES ON THE TAN-LU FAULT ZONE AND THEIR DEEP PROCESSES

作　　者：朱光[1] 刘国生[1] 牛漫兰[1] 宋传中[1] 王道轩[1] 

机构地区：[1]合肥工业大学资源与环境科学系,合肥230009

出　　处：《地震地质》2002年第2期265-277,共13页Seismology and Geology

基　　金：国家自然科学基金 (49872 0 74 )

摘　　要：郯庐断裂带晚第三纪以来持续遭受着挤压 ,使前期大规模的断陷盆地抬升、消亡 ,近代还是中国东部最大的地震活动带。断裂带所遭受的近WE向的挤压 ,是西太平洋弧后扩张和印度板块向北碰撞中的构造挤出作用产生的区域动力。断裂带在新生代挤压活动中切入上地幔 ,出现了地幔剪切、地幔交代、部分熔融等深部过程 。Thrusting time of the Tan Lu fault zone has been a controversial issue for long. Recently, many lines of evidence has proved that wide spread compression initiated on the fault zone between Eogene and Neogene, which has given rise to the uplift and consumption of many previous large faulted basins. Since Neogene period the fault zone has continued to suffer from compression, which resulted in many times of thrusting on the fault. The fault zone is currently the largest seismically active belt in eastern China. The compressive activities on the fault zone were dominated by thrusting with small amount of right lateral displacement sometimes and were often associated with the development of NW striking left lateral wrench faults. Margins of basins on the fault zone were intensely involved in the thrusting which caused the formation of shuttered zone and folds. Measurements of paleostress and present stress fields show that the fault zone has suffered nearly E W compression since Neogene due to the back arc spreading of the west Pacific Ocean and tectonic extrusion produced by the northward collision of the Indian Plate. Basalt eruption extensively occurred along the fault zone in Cenozoic, indicating that the fault zone cuts deeply into the upper mantle. Lithological character of the Cenozoic basalts demonstrates that the cutting depth of the fault increased from Paleogene to Quaternary gradually. Geoscience transects reveal obvious intensification of asthenoshperic upwelling beneath the Tan Lu fault zone, which demonstrates that the fault zone cut through the entire lithosphere. Deformed mantle derived xenoliths, such as mylonitic peridotite xenolith, in the basalts reflect that mantle shearing appeared in mantle involved by the fault. Metasomatic minerals in the xenoliths as well as geochemical features of the basalts and xenoliths all suggest that the involved mantle experienced extensive metasomatism. The mantle shearing and metasomatism are related closely and help each other. They also help parti

关 键 词：郯庐断裂带 挤压活动 深部过程 玄武岩喷发 地震活动带 

分 类 号：P542.3[天文地球—构造地质学] P315.2[天文地球—地质学]