351

Site number:

351

Authors:

IBC, GGC

Date recorded:

1972/12/11

Reason Sampled:

Soil weathering examination

Description:

On the S side of Wright Valley in Sessrumnir Valley, approximately 2.2km NNE of Mt Freya; at the N end of a high valley shoulder surface; the site is at the edge of the valley side escarpment of Wright Valley on a convex surface

Altitude:

1675 m

Aspect:

NNW

Slope:

7 °

Climate

Soil climate zone:

Central Mountain

Estimated mean annual temperature:

-25 °C

Frozen ground depth:

20 cm

Frozen type:

Hard ice-cemented

Frozen comment:

20cm

Geology

Geological setting:

Tills in the alpine valleys of the Asgard Range are among the oldest known in the Transantarctic Mountains and based on ash occurrences, date from the Miocene; the till sequences are complex with local alpine sourced moraine being distinguished from outside sources by the presence of granite erratics; the till at this site is above the granite erratic moraine appears to be of local origin with less sandstone

Patterned ground:

Weakly developed broad nets

Surface weathering or surface features:

Dolerite boulders mostly rounded and some fracturing with some ventiform shapes; strong pitting on fine grained clasts; some dolerite cavernously weathered; coarse dolerite with granular disintegration and moderate exfoliation; sandstone clasts strongly stained and very small; a moderately developed cobble/boulder pavement; salts beneath surface stones

Soil

Soil parent material:

Well oxidised bouldery till from dolerite with some sandstone

Previous disturbance:

Nil

Soil weathering stage:

6 5 (Campbell & Claridge 1975)

Soil moisture status:

A dry site with no snow nearby

Biological activity:

Nil observed but endolithic algae present in some sandstone outcrops