The Pagodroma Group – a Cenozoic record of the East Antarctic ice sheet in the northern Prince Charles Mountains

B.C. McKelvey, M.J. Hambrey, D.M. Harwood, M.C.G. Mabin, P.-N. Webb, J.M. Whitehead
2001 Antarctic Science  
The northern Prince Charles Mountains overlook the western side of the 700 km long Lambert Glacier-Amery Ice Shelf drainage system. Within these mountains, at Amery Oasis (7O05O'S, 68'00'E) and Fisher Massif (7 1' 3 1 'S, 67"40'E), the Cenozoic glaciomarine Pagodroma Group consists of four uplifted Miocene and Pliocene-early Pleistocene formations here named the Mount Johnston, Fisher Bench, Battye Glacier and Bardin Bluffs formations. These are composed of massive and stratified diamicts,
more » ... er gravels and minor laminated sandstones, siltstones and mudstones. Each forniation rests on either Precambrian metamorphic rocks, or on Permo-Triassic fluvial strata. The unconfonnity surfaces are parts of the walls and floors ofpalaeofjords. TheMiocene FisherBenchFormationexceeds 350 minthickness at Fisher Massif, where the yet older Miocene (or Oligocene) Mount JohnstonFormation overlies basement rocks atup to 1400 mabove sea level. Individual formations contain either Miocene diatoms, or else Pliocene-early Pleistocene diatomforam assemblages. The diamicts are interpreted as fjordal ice-proximal or ice-contact sediments, deposited seawards of tidewater glacier fronts located some 250 to 300 km inland of the present ocean margin. Each formation records an ice recession following a glacial expansion.
doi:10.1017/s095410200100061x fatcat:rf2ucshn2rbzhfbgeffo2psbui