641

Site number:

641

Authors:

IBC, GGC, MRB

Date recorded:

1991/12/04

Reason Sampled:

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

Description:

About 20m to the west of the northern end of the Marble Point runway and east of a small lake; a flat dry hollow, possibly water filled at times; about 10m from the northern edge and about 15m SE from site 640; the hollow may be an old kettle hole

Altitude:

70 m

Aspect:

Nil

Slope:

0 °

Climate

Soil climate zone:

Coastal Antarctic

Estimated mean annual temperature:

-18 °C

Frozen ground depth:

35 cm

Frozen type:

Hard ice-cemented

Frozen comment:

35cm

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:

Nil

Surface weathering or surface features:

Surface rocks are angular and unstained; some fragmenting and partly crumbled

Soil

Soil parent material:

Slightly gravelly silty sand

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:

The soil is slightly moist; the site probably becomes ponded at times from thawing of snow patches as dried cyanobacterial mats are common on the soil surface

Biological activity:

Dried cyanobacterial mat residues over much of the soil surface