The stratigraphy of the Pliocene—lower Pleistocene Bardin Bluffs Formation, Amery Oasis, northern Prince Charles Mountains, Antarctica

• Published in: Antarctic Science
• Main Authors: Whitehead, J.M., McKelvey, B.C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2001
• Subjects: Geology; Ecology, Evolution, Behavior and Systematics; Oceanography; Antarctic; East Antarctic Ice Sheet; Amery; Amery Ice Shelf; Prince Charles Mountains; Lambert Glacier; Bardin Bluffs; Pagodroma Gorge; Antarc*; Antarctic Science; Antarctica; Ice Sheet; Ice Shelf
• Online Access: http://dx.doi.org/10.1017/s0954102001000128; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102001000128

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.