505

Site number:

505

Authors:

IBC, GGC

Date recorded:

1983/01/15

Reason Sampled:

Soil characterisation

Description:

On the western side of the upper portion of the valley floor surface of the Northwind Valley, 7.5km west of Larsen Crag; a surface which is about 40m above that of site 504 and .5km to the SW; this surface appears to be older and more weathered than the surface below

Altitude:

1150 m

Aspect:

NE

Slope:

2 °

Climate

Soil climate zone:

Central mountain

Estimated mean annual temperature:

-26 °C

Frozen ground depth:

19 cm

Frozen type:

Hard ice-cemented

Frozen comment:

19cm

Geology

Geological setting:

The surface is a small shelf and is formed below a prominent bench that encircles the head of the valley; till covers the surface and is dominated by coarse and fine grained dolerite but some fragments of pink granite are present, which suggests a down-valley source or an early up-valley ice invasion, possibly from a previously enlarged Fry Glacier or a former West Antarctic Ice Sheet expansion

Patterned ground:

Weakly developed nets with shallow 20-30cm troughs; appears to be inactive

Surface weathering or surface features:

A well developed desert pavement with rounded, flattened, moderately pitted and strongly stained surface stones; few upstanding boulders which show marked sculpturing and cavernous weathering; salts beneath some surface stones

Soil

Soil parent material:

Bouldery till from dolerite, granite and sandstone

Previous disturbance:

Nil

Soil weathering stage:

6 4 (Campbell & Claridge 1975)

Soil moisture status:

Xerous; no snow patches, snow banks or seepage nearby but the lower horizons above the permafrost are slightly moist

Biological activity:

A few small occurrences of lichens in cracks of rocks