Crustal analysis of maud rise from combined satellite and near-surface magnetic survey data

Abstract

Abstract We produced a crustal magnetization model for the Maud Rise in the southwest Indian Ocean off the coast of East Antarctica using magnetic observations from the Ørsted satellite and near-surface surveys complied by the Antarctic Digital Magnetic Anomaly Project (ADMAP). Joint inversion of the two anomaly fields suggests that the magnetic effects due to crustal thickness variations and remanence involving the normal polarity Cretaceous Quiet Zone (KQZ) dominate at satellite altitude (~700 km). The crustal thickness effects were modeled in the Ørsted data using crustal thickness variations derived from satellite altitude gravity data. Modeling of the residual Ørsted and near-surface magnetic anomalies supports extending the KQZ eastwards to the Astrid Ridge. The remaining near-surface anomalies involve crustal features with relatively high frequency effects that are strongly attenuated at satellite altitudes. The crustal modeling can be extended by the satellite magnetic anomalies across the Indian Ocean Ridge for insight on the crustal properties of the conjugate Agulhas Plateau. The modeling supports the Jurassic reconstruction of Gondwana when the African Limpopo-Zambezi and East Antarctic Princess Astrid coasts were connected as part of a relatively demagnetized crustal block.