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SUMMARY:Revealing the Antarctic continent with recent aerogeophysical expl
 oration - Dr Fausto Ferraccioli\, British Antarctic Survey
DTSTART:20120307T163000Z
DTEND:20120307T173000Z
UID:TALK34002@talks.cam.ac.uk
CONTACT:Steven Palmer
DESCRIPTION:The Antarctic continent plays a pivotal role in global Earth S
 ystem. The major ice sheets that cover the continent are a key influence o
 n both  global sea level rise and the climate system\, and the underlying 
 geology is a critical piece of the puzzle for studies of supercontinental 
 evolution and processes.\n\nI will review some recent aerogeophysical expl
 oration projects that the British Antarctic Survey has been performing tog
 ether with its national and international collaborators over the last deca
 de to help unveil both the geological structure of the continent and to as
 sist in studying ice sheet  behaviour\, through an improved knowledge of b
 asal conditions and englacial structures. In particular I will be focussin
 g on our latest major aerogeophysical exploration campaign over the enigma
 tic Gamburtsev Subglacial Mountains in interior East Antarctica that was a
 chieved by major international collaboration during the International Pola
 r Year.\n\nAlthough coupled climate and ice sheet models have suggested th
 at the Gamburtsevs were a key nucleation site for the early formation and 
 evolution of the Antarctic ice sheet the origin of this high elevation mou
 ntain range in an apparently stable Precambrian shield has remained an unr
 esolved mystery ever since their first discovery some 50 years ago. With t
 he aid of combined radar\, gravity and magnetic measurements we investigat
 ed the structure and the processes that created the Gamburtsevs. We propos
 e that a thick crustal root was formed under the Gamburtsevs province when
  different parts of East Antarctica came together (collided) perhaps a bil
 lion years ago or more. Normally these old roots are lost in the mantle\, 
 but here the root was preserved\, probably becauseit was very dense and dr
 y\, as is the case for example in the Urals or the TransHudson Orogen. Abo
 ut 250 Ma ago\, and then again about 100 Ma\, a major rift system that ext
 ended for over 3\,000 Km from India to South Pole reactivated the old root
  and through a processes known as flexure helped uplift the range. However
 \, the modern Gambuirtsevs achieved their present day rugged Alpine topogr
 aphy through later valley incision processes that helped uplift the peaks.
  The remarkable preservation of the mountain range is linked to extremely 
 low erosion rates that are due to the overlying cover by the East Antarcti
 c Ice Sheet\, as Antarctica plunged into an icehouse world some 34 Ma.\n\n
 Testing the new geophysical models for the Gamburtsevs now require and eve
 n great challenge: drilling through several thousand meters thick ice (in 
 places)to get samples. Ambitious plans for drilling are already on the Chi
 nese research agenda\, in particular to try and find the oldest ice of our
  planet and perhaps recover a rock sample!
LOCATION:Scott Polar Research Institute\, main lecture theatre
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