438

Site number:

438

Authors:

IBC, GGC

Date recorded:

1978/11/19

Reason Sampled:

Soil weathering examination

Description:

The Darwin Mountains, just to the south of the Midnight Plateau; on a sloping surface adjacent to the edge of the Midnight Plateau ice and snow front;

Altitude:

1650 m

Aspect:

SW

Slope:

10 °

Climate

Soil climate zone:

Central Mountain

Estimated mean annual temperature:

-35 °C

Frozen ground depth:

11 cm

Frozen type:

Hard ice-cemented

Frozen comment:

11cm

Geology

Geological setting:

Rock outcrops on the area are Ferrar Dolerite; the ground surfaces have been exposed following retreat of ice from the Midnight Plateau; close to the ice edge, the soils are less weathered but distinct successional surfaces marking ice retreat are not present; although close to the ice edge, there is distinct surface and soil weathering; the weathering is probably relict and not directly related to the present ice cover

Patterned ground:

Weakly developed broad nets

Surface weathering or surface features:

Surface boulders are subangular but with well rounded edges; the pavement weakly to moderately developed with upstanding boulders to 60cm; clasts are moderately to strongly stained with strong polish on fine grained clasts; exfoliation of weathering skins is active; coarse grained clasts show distinct granular disintegration

Soil

Soil parent material:

Gravelly till from dolerite with a small amount of sandstone present

Previous disturbance:

Nil

Soil weathering stage:

6 4 (Campbell & Claridge 1975)

Soil moisture status:

Extensive snow patches but little ablation against rock surfaces and no thaw or soil moistening

Biological activity:

Nil observed