考虑沉积层重力改正的中国西部Moho面深度反演

Inversion of Moho Depth in Western China Considering Gravity Correction of Deposition Layer

首先研究了大型沉积盆地对地表重力异常的影响,然后基于Parker-Oldenburg迭代算法,利用经过沉积层改正的布格重力异常数据反演了中国西部的Moho面深度。结果表明,地壳浅层密度异常对地表重力异常和Moho面深度结果的影响较大,利用简化的三层沉积层模型,计算出的中国西部沉积盆地的重力异常改正最大可达25 m Gal,由此引起的Moho面深度可达2.2 km,Moho面深度最终计算结果与区域最新研究成果相符合,因此,利用重力异常反演Moho面深度时,应考虑沉积层的影响以提高反演精度。

Firstly, the influence of the huge sedimentary basin on the surface gravity anomaly was studied. Secondly, based on the Parker-Oldenburg iterative algorithm, we inversed the depth of Moho surface in Western China by using the Bouguer gravity anomaly data after the correction of the sedimentary. The results show that the shallow density anomaly in the crust had the great influence on both surface gravity anomaly and the depth of Moho sur- face. Using the simplified 3-layers sedimentary model, we obtained that the gravity anomaly correction can be up to 25 reGal in the sedimentary basin in Western China, which induced the depth of Moho surface is 2. 2 km, and the calculated depth of Moho surface is corresponding to the latest regional research result. In order to get better accuracy of the depth of Moho surface, the sedimentary effects should be considered in the process of inversing the depth of Moho surface by using gravity anomaly.