南宁新生代软流圈上涌柱及其对浅表构造的影响

摘要：在研究南宁新生代软流圈上涌柱构造的基础上,从过渡构造、区域断裂、新生代盆地等方面并结合三维数值模拟来进一步分析和研究南宁新生代软流圈上涌柱构造对浅表构造的影响。南宁新生代软流圈上涌柱的存在对研究区浅表构造的影响是深层次、多方面的,在柱体边缘形成一系列过渡构造,影响到柱体中心附近NE向和NW向区域断裂的分段活动性。同时,在软流圈上涌和向东南方向流动过程中,带动研究区地壳上部块体移动,在南宁新生代软流圈上涌柱的柱体中心、西部和北部产生引张,相应在浅表形成断陷盆地,同时加强了东南部NE向和NW向区域性断裂的活动性,形成了灵山“中强地震活动区”。三维数值模拟的结果进一步验证了这个结论。

Nanning Cenozoic asthenosphere upwelling plume and its influence on the shallow surface structure.

Based on the integrated research of intermediate structure, regional faults, Cenozoic basins and three dimensional numerical simulation, we further analyze the impact of the Nanning Cenozoic asthenosphere upwelling plume tectonics on the shallow surface structure of the study area. A series of transitional structures, generated at the margin of the asthenosphere upwelling plume, affect the activities of NE trending and NW trending regional faults near the central of plume. Simultaneously, during the asthenosphere upwelling and flowing to southeast, the plume caused the movement of the upper crust mass, which led to the following events: the extension of the center, the west and the north of the plume; the formation of fault basins on the shallow surface; the enhancement of the activity of NE trending and NW trending regional faults in the southeast; the generation of the Lingshan mid strong seismic active region. The conclusion has further been tested by the three dimensional numerical simulation.