504

Site number:

504

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 broad, slightly undulating, moderately weathered till-covered surface

Altitude:

1100 m

Aspect:

NE

Slope:

2 °

Climate

Soil climate zone:

Central mountain

Estimated mean annual temperature:

-26 °C

Frozen ground depth:

30 cm

Frozen type:

hard ice-cemented

Frozen comment:

30 cm

Geology

Geological setting:

The surface is formed below a prominent bench that encircles the head of the valley; the till is dominated by dolerite but contains some pink granite, 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:

Moderately developed patterned ground across the surface but the surface expression is somewhat subdued with cracks less than 50cm deep

Surface weathering or surface features:

Occasional upstanding boulders and these have weak cavernous weathering; most surface boulders are small, (250-750mm) flattened, subrounded abraded and stained; minor pitting occurs on fine grained dolerite rocks; the pavement surface is moderately developed;

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 but the lower 15cm of the soil above the frozen ground is moist

Biological activity:

A few small occurrences of lichens in cracks of rocks