Gravity anomaly characteristics of sedimentary basin of Weddell Sea in Antarctica

The latest gravity data calculated from satellite altimetry are tested and verified by the marine gravity data collected in Antarctic Weddell Sea, and the Parker forward method is used to obtain the Bouguer gravity anomaly in the Weddell Sea sedimentary basin. In order to explore the relationship between gravity anomalies and wavelength in the Weddell Sea sedimentary basin, a sedimentary basin model is established to calculate the ratio of the gravity effects of the Moho compensation to sedimentary process. Further, Airy-Hesikanen isostatic model is used to calculate the isostatic anomaly and explore the isostatic state of the boundary. The results show: (1) The Bouguer gravity anomaly in the Weddell Sea sedimentary basin has different characteristics with wavelength changes: the Bouguer gravity anomaly with a wavelength of 200 similar to 600 km (corresponding to a sedimentary basin with a width of 100 similar to 300 km) is mainly positive, while the wavelength is 80 similar to 200 km (corresponding to a sedimentary basin with a width of 40 similar to 100 km), the Bouguer gravity anomaly is negative. (2) Further analysis based on the gravity anomaly model of sedimentary basins with varying flexural rigidities shows that the positive gravity anomaly in Weddell Sea may be not formed by the long-term underplating in the crust, but the interaction between sedimentation and rifting. (3) The isostatic gravity anomalies of the sea-land boundary in this region presents high negative values, reflecting that the sedimentary process of the Weddell Sea Basin is related to the ice shelf displacement system.