INDIA-ANTARCTIC BREAKUP: CONSTRAINTS FROM NEW GEOPHYSICAL DATA

• Main Authors: Jokat, Wilfried, Altenbernd, Tabea, Geissler, Wolfram, Eagles, Graeme
• Format: Conference Object
• Language: unknown
• Published: Berichte zur Polarforschung, 716 2018
• Subjects: Antarctic; East Antarctica; Indian; Kerguelen; Prydz Bay; Antarc*; Antarctica; Berichte zur Polarforschung; Enderby Land; Polarforschung
• Online Access: https://epic.awi.de/id/eprint/46830/; https://hdl.handle.net/10013/epic.85f890ac-f3d8-4e6a-82b9-9845e2f6ef9e

The India-Antarctica separation is still an open problem due to the absence of critical geophysical data. So far no wide-angle data existed along the conjugate margins of East India and the Enderby Land off East Antarctica to define the position and composition of the continent-ocean boundary - a pre-requisite for any sound reconstruction. Furthermore, along both margins only old marine magnetic random track data are available for identifying seafloor spreading anomalies to describe the drift of both continents in the Cretaceous. The Kerguelen Plateau, located just north of the East Antarctica coast, however, has been drilled several times providing the only reliable age constraint on the formation of this huge magmatic plateau. In general, the poor information resulted a wide variety of kinematic models for the drift of the India. In the last years several newly acquired geophysical data provide new constraints on its drift. Two deep seismic sounding lines off Prydz Bay and across the Princess Elisabeth Trough show that oceanic crust is already present much closer to the present-day shelf break than previously known. Magnetic data acquired parallel to these lines provide excellent timing constraints for the initial breakup of India. Finally, marine magnetic data gathered in 2017 south of Sri Lanka indicate that here the oceanic crust is definitely younger than magnetic chron M0, questioning several kinematic models for the Indian Ocean. The latest results will be presented.