Here's what USGS Professional Paper 591, Descriptive Catalog of Selected Aerial Photographs of Geologic Features in areas outside the United Sates has to say about the dry valleys of Antarctica. I've added my personal comments.
The Taylor Dry Valley extends 32 kilometers from
the Taylor Glacier to McMurdo Sound. Small highland ice sheets in the
Asgard Range nourish two expanded-foot glaciers, the Commonwealth
glacier and the Canada glacier.
PD: These glaciers were even more spectacular in person than in their
aerial photographs. The vertical cliffs at their ends are
amazing.
The drainage of lower Taylor valley is up valley
into lakes Fryxell and Chad because a glacial tongue from McMurdo
Sound once occupied the valley.
PD: I wondered why the streams flowed up valley.
Dust blown downvalley accentuates cracks in the
sea ice on McMurdo Sound.
PD: As Mary Miller and I flew in to the dry valleys we admired the
wonderful pattern of broken sea ice revealed by the dust.
Metasedimentary and granitic rock underlie this
region.
PD: I saw these rocks broken by temperature change and freeze thaw
and weathered by windblown snow into ventifacts.
Commonwealth Glacier is an expanded-foot glacier
with vertical terminal walls about 10 meters high.
PD: While I was at Lake Hoare camp surveyors measured the height of
the walls to be closer to 20 m.
There are radial crevasses deeply etched by
ablation and ephemeral meltwater.
PD: I was privileged to see some of the ephemeral meltwater in
action.
The Professional Publication was published in
1969, the air photographs of Taylor Dry Valley were taken in
1957.
PD: I still have the book after all these years.
The photos were available as 9 x 9 inch contact prints costing $1.
|
Scientific Explorations with Paul Doherty |
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5 July 2002 |