The Beardmore Fjord

The sediment of unit 1 of the Meyer Desert Formation at Oliver Bluffs also contains marine forams (McKelvey et al. 1991) indicating that the present Dominion Range was within the Beardmore Fjord during the Pliocene at least part of the time. 

We recall at this point that the Transantarctic Mountains consist of several large fault blocks which were uplifted at different rates and different times. Therefore, the differential uplift of the fault blocks may have affected their glacial histories, such that low-lying areas experienced overriding glaciations, whereas up-faulted blocks remained ice-free at the same time. 

Lodgment till and associated periglacial outwash deposits occur widely in the Transantarctic Mountains. Although all of the Cenozoic glacial deposits are now included in the Sirius Group, these deposits are difficult to date because the microfossils they contain are reworked and because the various kinds of plant ronains they may contain are not sufficiently time-sensitive to determine their depositional ages. 

The Queen Maud glaciation of Mayewski (1975) is based on the till on the summit of Mt. Sirius ( 4.2 Ma) which he considered to be early Pliocene in age, whereas Webb et al. (1987) and Webb and Harwood (1987) preferred a late Pliocene age ( 3.5 Ma) based primarily on the age of the youngest reworked microfossils (e.g., marine diatoms). 

Mayewski (1975) used the elevations of the lateral moraines to project the level of ice in the outlet glaciers to the East Antarctic ice sheet. The resulting ice-sheet reconstruction indicated that during the Queen Maud Glaciation the Transantarctic Mountains were almost completely covered by ice and that the ice sheet along the central divide in East Antarctica was about 350 m thicker than it is at the present time. In addition, the grounding line of the Ross Ice Shelf moved forward to a position 225 km north of the present edge of the ice shelf. 

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