重力异常转换梯度在琼东南盆地构造识别中的应用

Application of calculated gravity gradient anomalies in recognizing structures in the Qiongdongnan Basin

为了了解琼东南盆地的深部地质构造分布特征,利用频率域中由重力异常换算重力梯度异常的计算式,通过模型的建立和试算,分析重力梯度异常特征,并在获取琼东南盆地重磁异常数据的基础上,求其重力异常梯度张量异常,从6个分量异常特征中分析和识别盆地内断裂位置、走向,以及密度异常体的分布,从而获取琼东南盆地的基底断裂构造分布。

In order to understand the distribution of tectonic units in depth of the Qiongdongnan Basin, we deduced a formula to convert gravity anomalies to gravity gradient anomalies, built models, calculated their gravity gradient tensors, and analyzed the characteristics of gravity gradient anomalies. On these bases, we gathered gravity and magnetic anomaly data of Qiongdongnan Basin on site, and calculated the gravity gradient tensors utilizing bouguer gravity anomalies. Then we analyzed anomalous char- acters of six gravity gradient tensors, tracked the location and strike of faults, and defined the distribution of anomalous density bodies in the basin. Finally, we ascertained the distribution of basement fault structures of the Qiongdongnan Basin. The results are consistent with the those based on other methods in terms of the main fraetural structures.