中国布格重力异常水平梯度图的判读和构造解释  

Analysis and tectonic interpretation to the horizontal-gradient map calculated from Bouguer gravity data in the China mainland

作　　者：马宗晋[1] 高祥林[1] 宋正范[2] 

机构地区：[1]中国地震局地质研究所,北京100029 [2]国土资源部航空物探遥感中心,北京100083

出　　处：《地球物理学报》2006年第1期106-114,共9页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(49834002)资助.

摘　　要：分析和对比中国大陆布格重力异常水平梯度的彩色图像,得到一些新的构造特征信息.大致以105°E为界,图像的东部以蓝色低梯度为背景,出现中、高梯度带状构造和大梯度差值边界的线状构造;西部以高、中梯度的带状构造为格架,镶嵌着低梯度区,区内有阴影线状构造.总体上,重力异常水平梯度构造可概括为三大组.第一组是NNE向的大兴安岭、太行山、武陵山高梯度带与斜切东部全区的郯庐大断裂带和NNW向的斜切西部全区的三条大断裂带;第二组为西部的NWW向与NEE向高、中梯度带的交叉构造格局,以及东部近于等间距的三条NWW向断续的阴影构造带和一条单一的构造线,而华南则仅有NE向的低梯度构造线;第三组是横贯全区的的几条近EW向和中部SN向宽而复杂的构造带,在后者的东、西两侧散臣着大间距、小长度、断续的SN向阴影构造线.这三组重力梯度构造不仅反映了地貌起伏的信息,而且显示了大区域构造,特别是深部构造的密度差.各组线状构造带的内部结构和各组的形成时间及演变历史可能不同,但它们相互复合构成现今总体的构造格局,对大尺度现代构造应力场作用都会有不同的响应,因此导致主应力方向的区域性变化.We make a careful analysis and comparison to the colored map of horizontal-gradient calculated from Bouguer gravity data of the China mainland, and obtain some new insights into tectonics. Taking roughly 105°E as the boundary in the map, its eastern part of the China mainland is characterized by low gradient （blue color） background, appearing belt-shape structure of medium and high gradients as well as linear structure of gradient difference border. The west part has a framework of belt-shape structure with medium and high gradient （red color）, inlaid by low gradient areas which contain shade-line structure. In general, structures exhibited by horizontal gradient of gravity anomaly can be classified into three major sets. The first set includes high-gradient zones along the NNE trending Daxinganling, Taihangshan, and Wulingshan mountains, the Tanlu great fault zone which extends obliquely through east China, and three NNW trending great fault zones through west China. The second set presents an intersection pattern of NWW and NEE direction gradient zones in the west, as well as three NWW discontinuous shade zones with roughly equal intervals, and a single tectonic line in the east, plus NE trending low gradient line in South China. And the third set consists of several EW tectonic zones through the whole mainland and a wide complex NS strike zone in the middle of the mainland, of which on the both sides spread NS direction shade lines which are short, discontinuous and of large intervals. These three sets of tectonic zones delineated by gravity gradient are associated with variations of topography and crustal thickness on a large scale. The inner structures and formation times as well as evolution histories of each set are likely different. They have overlapped each other to shape the current tectonic pattern of the China mainland. Each tectonic zone has varied response to the recent tectonic stress field of large scales, leading to regional change of directions of principle stresses. The ubiquitous segm

关 键 词：中国大陆 重力异常水平梯度 构造分段性 

分 类 号：P312[天文地球—固体地球物理学]