639

Site number:

639

Authors:

IBC, GGC, MRB

Date recorded:

1991/12/03

Reason Sampled:

Soil moisture & permafrost investigations; toposequence and landscape relationship differences; first in sequence

Description:

About 200m to the west of the northern end of the Marble Point runway and east of a small lake; a slightly hummocky low moraine ridge alongside and north of a small flat hollow; on the crest of the ridge; the first of a series of adjacent sites

Altitude:

75 m

Aspect:

Nil

Slope:

0 °

Climate

Soil climate zone:

Coastal Antarctic

Estimated mean annual temperature:

-18 °C

Frozen ground depth:

49 cm

Frozen type:

Hard ice-cemented

Frozen comment:

49cm

Geology

Geological setting:

The surface is undulating with deposits of till; the region is an old landscape of granite and granodiorite, gneiss and marble rocks; there are some old weathering and phillipsite deposits in the region; the till has probably come from the Wilson Piedmont Glacier and includes granodiorite, gneiss, marble and some dolerite; the till is silty in places and this may have resulted from postglacial fluvial activity

Patterned ground:

Nets 15-20m across with active cracks 20-30cm deep

Surface weathering or surface features:

Non pavementic with predominantly small boulders and cobbles and subangular to angular; distinct oxidation and staining on some clasts may in part be pre-weathering

Soil

Soil parent material:

Sandy to silty granitic and granodioritic stony till

Previous disturbance:

Extensive construction, earthmoving and human activity in the late 1950's in the general area; some nearby bulldozer tracks

Soil weathering stage:

1 (Campbell & Claridge 1975)

Soil moisture status:

Patchy snow on adjacent side slopes; soil surface is dry

Biological activity:

Some yellow lichen in patterned ground cracks; also some black dried cyanobacterial matter; some nearby moss patches