The Cretaceous-Tertiary sea floor off Dronning Maud Land, Antarctica

Abstract

A study of the bathymetric and linear magnetic anomalies between Dronning Maud Land, Antarctica and the South West Indian Ridge (SWIR) revealed a Mesozoic sequence of linear magnetic anomalies, M0 to M12 (108-126 Ma), a fracture zone offset (is approx. equal to 130 km), and the Cretaceous magnetic quiet zone between isochrons M0 (108 Ma) and 34 (80 Ma). The study sheds light on: (1) the evolution of an anomalous "stretched" pattern of seafloor anomalies during magnetic isochrons M0 and 34, and the associated offset (greater than 10 degrees) in some segments of the northeastern part of the SWIR; and (2) continuation of a proposed buried fracture zone to the south, where it abuts the Astrid Ridge off Dronning Maud Land. The history of spreading is related to dynamic pressures at the plate margin due to the Kergeulen-Heard mantle plume during Cretaceous time (is approx. equal to 110 Ma)