Ross-Sea Glaciation

During the Pleistocene, McMurdo Sound was filled with the ice of the grounded Ross Ice Shelf. The Ross-Sea drift that was deposited by this ice is largely unweathered, is underlain by residual bodies of ice, and is bounded by terminal moraines (Stuiver et al. 1981). These deposits occur primarily along the western coast of McMurdo Sound including the Brown 

Peninsula, the ice-free valleys along the north side of the Koettlitz Glacier (Garwood, Marshall, and Miers valleys), at the mouth of Taylor Valley, and in the eastern part of Wright Valley. In addition, Ross-Sea drift occurs on Minna Bluff, Black Island, and along the coast of Ross Island (Clapperton and Sugden 1990). 

The C-dates of algal mats in Taylor Valley in Fig. 19.28 increase with increasing elevations of the collecting sites such that the oldest dates between 16,000 and 

200 years bp. apply to algal mats collected at high elevation between 80 and 230 m a.s.l. This pattern of variation, though inexact, indicates that high levels of water persisted in Taylor Valley for about 5,200 years from 21,200 to about 16,600 years bp. when the level Lake Washburn began to decline until the end of the Pleistocene at about 8,300 years bp ( = before present). 

The lakes that exist in Wright and Taylor valleys at present still contain algae that grow in the warm brines at the bottom of the largest lakes (e.g.. Lake Vanda in Wright Valley and Lake Bonney in Taylor Valley). 

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