塔里木盆地重磁场特征与基底结构分析

根据塔里木盆地的布格重力与航磁资料,通过不同高度的解析延拓、不同方向水平梯度计算,分析了盆地内部与盆地边缘重磁场特征的差异,并反演计算了基底起伏与莫霍面深度。结果显示：盆地内部重磁异常变化相对平缓,盆地边缘变化剧烈；莫霍面形态中部上隆,盆地南北边缘分别向南、北加深；盆地边缘的前陆盆地表现为基底深凹；盆地边缘断裂特征与内部有所不同,边缘断裂基本平行于盆地边界,规模大,延伸长。反映了刚性的塔里木岩石圈在印藏碰撞的远距离效应下发生挠曲与整体变形,盆地边缘发育大型断裂系统,使应变能主要在周边变形最强烈的区域释放,形成了盆地周边比盆地内部活动强烈的特点。

Features of Gravitational and Magnetic Fields in the Tarim Basin and Basement Structure Analysis

In terms of gravitational and magnetic anomaly data, various information after the processing (upward continuation and horizontal direction derivative, etc.) , the features of gravitational and magnetic field in the Tarim Basin are analyzed. The basement depth and the Moho depth are also computed. The gravitational and magnetic anomalies vary changefully on the basin edge and gently inside the basin. The Moho upheaves at the basin center and dips toward the basin edge. The basement depressions appear at the foreland basin. The faults of edge are parallel to basin boundary and extend to large scale. It may be explained that the rigid lithosphere is flexed and the large faults are developed at the basin edge due to the remote effects from the India and Qinghai-Tibet collision. The energy is mainly released during the activity of faults, and the activity on basin edge is stronger than in the basin interior.