Geoscience Reference
In-Depth Information
Fig. 11.10
A comparison of landform surfaces in Antarctica and Mars (Source: NASA)
from 2.5 to 5 Ma in age from the Arctic, Antarctica, and the high mountains of
Siberia. Samples collected from the Antarctic dry valleys were analyzed for biodi-
versity, state, and age (Gilichinsky et al.
2007
).
11.9
Cryosols and High-Level Lakes
in the McMurdo Dry Valleys
According to Hall et al. (
2000
), a high-water-level (336 m) lake, Glacial Lake
Washburn, existed throughout Taylor Valley during the Last Glacial Maximum
(LGM) and early Holocene, ca. 18.6-6.0 ka. They projected that this lake was
38 km
2
in area and had a maximum depth of 300 m. Hall et al. (
2001
) and Hall and
Denton (
2005
) proposed the existence of Glacial Lake Wright, a high-water-level
(550 m) lake, during the LGM and early Holocene, ca. 2.7-25.7 ka in Wright Valley.
They proposed that this lake was 212 km
2
in area and had a maximum depth of
470 m. Hall et al. (
2002
) suggested that a 185-m deep lake may have engulfed most
of the Victoria Valley system between 20 and 8.6 ka. The primary evidence for high-
level lakes is the presence of deltas containing cyanobacterial mats that have been
radiocarbon dated.
