Disclosing secrets of the Antarctic lithosphere with recent airborne and satellite geophysics

Thursday November 29 at 2:30 pm in Physics, rm 103, presented by Dr. Fausto Ferraccioli, Senior Geophysicist at the British Antarctic Survey (BAS/NERC) where he is Head of Airborne Geophysics since 2002 (he has been the Science Leader of the Geology and Geophysics Team of BAS since April 2015):

Disclosing secrets of the Antarctic lithosphere with recent airborne and satellite geophysics

The Antarctic lithosphere forms the cradle on which the Antarctic ice sheets flow. Prior to the breakup of Gondwana, some 180 million years ago, Antarctica was the keystone in a mosaic of continents including Australia, Zealandia, India, Africa and South America. The "lost" and more cryptic parts of these continents are now buried beneath several kilometre-thick ice sheets. Ultimately, it was the break-up of Gondwana that isolated Antarctica at the South Pole, and this enabled massive ice sheets to form, thrive and survive since the Eocene-Oligocene climate transition ca 34 million years ago.

Despite extensive international airborne geophysical exploration, in particular since the International Polar Year, several parts of Antarctica remained until recently "terra incognita" and our knowledge of the variability and influence of the lithosphere at continental (as opposed to regional) scale was relatively poor, compared to other formerly adjacent continents.

In this talk, selected highlights will be presented from ongoing continent-wide studies of the Antarctic lithosphere that are emerging from three major projects supported by the European Space Agency:

1) PolarGAP, an exciting new aerogeophysical exploration effort that is providing tantalising new clues into the bed topography, ice sheet and subice geology of the South Pole frontier- where not even satellites provided data before;

2) GOCE+Antarctica, an international effort that combines satellite gravity gradient analyses with seismology and petrological modelling to help unveil the variability in the thickness of the crust and the depth of the lithosphere-asthenosphere boundary. By doing this, the project also contributes towards better constraining the thermal state of the lithosphere, which in turn influences geothermal heat flux and upper mantle viscosity. Geothermal heat flux and mantle viscosity are particularly ill-constrained parameters for Antarctica, and yet they are critically important as they also influence subglacial hydrology and glacio-isostatic adjustment processes;

3) ADMAP 2.0+, a new project that leverages the latest Antarctic magnetic anomaly compilation that now includes a staggering 3.5 million line km of magnetic data. Overarching aims here are to help understand the large-scale variability in geological boundary conditions for the Antarctic ice sheet, while also linking the architecture and tectonic evolution of Antarctica with the supercontinent cycle much better than is currently possible.