Gravity anomaly in the southern South China Sea: a connection of Moho depth to the nature of the sedimentary basins' crust.

To study the distribution characteristics of the Moho interface and the relationship between the Moho depth and the main sedimentary basins in the southern South China Sea and its adjacent areas, this paper adopts gravity anomaly data and multi-scale decomposition of two-dimension discrete wavelet transform to analyse the gravity field and the characteristics of the multi-order decomposition in the study area. Through the method of Parker-Oldenburg Iterative Inversion, the Moho depth of the study area has been obtained based on four-order approximation of Bouguer anomaly and constrained by the data of the CRUST1.0 model. By analysis and comparison, the optimum inversion parameters and the final inversion results of the Parker-Oldenburg Iterative Inversion have been explored. The distribution of the Moho depth in the study area takes on a double 'V'-type characteristic. In addition, the Moho morphology of the three main kinds of basins in the study area has also been concluded. The crustal thickness of the sedimentary basin indicates, in the case of the nature of the basins' crust, that the transition from north to south is from continental crust to transitional crust. These results provide the basis for further study of the gravity field, the deep geological structure in the southern South China Sea and the prediction of oil and gas prospects. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]