The stratigraphy of the Pliocene-lower Pleistocene Bardin Bluffs Formation, Amery Oasis, northern Prince Charles Mountains, Antarctica
Whitehead, JM and McKelvey, BC, The stratigraphy of the Pliocene-lower Pleistocene Bardin Bluffs Formation, Amery Oasis, northern Prince Charles Mountains, Antarctica, Antarctic Science, 13, (1) pp. 79-86. ISSN 0954-1020 (2001) [Refereed Article]
In the Amery Oasis of the northern Prince Charles Mountains, the glaciomarine Bardin Bluffs Formation of the Pagodroma Group was deposited between the Late Pliocene (< 3.1 Ma) and Early Pleistocene (> 1 Ma). The formation provides evidence of (i) a reduced East Antarctic ice sheet compared to that of the present day and (ii) a subsequent Plio-Pleistocene ice sheet expansion. The formation consists of two members. The older, basal Member 1 is c. 12.5 m thick and consists of relatively ice-distal silty, sandy and sparsely fossiliferous fjordal strata. Member 1 reflects largely ice-free marine sedimentation c. 250 km inland from the current Amery Ice Shelf edge. The member is restricted to the area about the north-eastern end of Pagodroma Gorge where it infills a chemically weathered erosion surface, cut in the form of a valley on the Permo-Triassic Amery Group. Weathering occurred during aerial exposure of the Amery Oasis in a warmer climate than that of today. The younger Member 2 exceeds 40 m in thickness and is made up of coarse ice proximal glaciomarine diamicts. It overlies disconformably Member 1 at Pagodroma Gorge. Elsewhere, Member 2 rests directly upon a smoothed and striated erosion surface, cut on the Amery Group, which was part of a fjord floor. This erosional surface and the facies contrast between the two members, indicates an East Antarctic Ice Sheet expansion and Lambert Glacier grounding-line advance.