622

Site number:

622

Authors:

IBC, GGC, MRB

Date recorded:

1991/11/25

Reason Sampled:

Soil moisture and permafrost investigations

Description:

Approximately 4.4km NW of Marble Point peninsula and 250m NW of the Marble Point Air Facility buildings; on a knoll of moraine about 5m high that forms a low hummocky ridge; on the ridge crest

Altitude:

75 m

Aspect:

N

Slope:

0 °

Climate

Soil climate zone:

Coastal Antarctic

Estimated mean annual temperature:

-18 °C

Frozen ground depth:

50 cm

Frozen type:

Hard ice-cemented

Frozen comment:

50cm

Geology

Geological setting:

The surface is a gently undulating till plain formed by retreat of the Wilson Piedmont Glacier; the Marble Point region is an old landscape, with deposits of phillipsite, buried soils and oxidised gneiss, which have been covered by advances of the grounded Ross Ice Shelf; later ice retreat and glaciological features have been controlled by changes in the stranded Wilson Piedmont Glacier; the till mantle is patchy and dominated largely by locally occurring rocks; granodiorite, granite, marble, gneiss, and dolerite

Patterned ground:

10-15m nets with 15-20cm troughs; open cracks, some partly snow filled

Surface weathering or surface features:

A predominantly cobble pavement with some boulders; surface granules are angular and mainly unstained; grey calcium carbonate coatings on undersides of many surface stones; granular disintegration of marble clasts and some oxidation of gneissic clasts

Soil

Soil parent material:

Bouldery till from marble; granodiorite, gneiss and other rocks

Previous disturbance:

Extensive mechanical and human activity in the region since the mid-1950's; a pit examined 3m away in 1990

Soil weathering stage:

1 (Campbell & Claridge 1975)

Soil moisture status:

A dry site, no adjacent snow patches or soil moistening

Biological activity:

Nil at site; moss patches and cyanobacteria are common locally