439

Site number:

439

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 flat moderately bouldery surface to the south of the Midnight Plateau ice and snow front; approximately 100m to the south of site 439

Altitude:

1650 m

Aspect:

Nil

Slope:

0 °

Climate

Soil climate zone:

Central Mountain

Estimated mean annual temperature:

-35 °C

Frozen ground depth:

29 cm

Frozen type:

Hard ice-cemented

Frozen comment:

29cm

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 appear less weathered but distinct successional surfaces marking ice retreat are not present; with increasing distance away from the ice front, soil weathering increases; the weathering is probably relict and unrelated to the present ice cover; sandstone erratics may indicate the presence of till derived from the Hatherton Glacier rather than the Midnight Plateau

Patterned ground:

Inactive broad nets;

Surface weathering or surface features:

Surface rocks are moderately rounded, strongly stained and moderately pitted; active surface exfoliation of weathering rhinds; sandstone clasts mainly unoxidised; a moderately developed pavement between bouldery clasts; some weak to moderate ventiforms

Soil

Soil parent material:

Gravelly till from dolerite with some sandstone

Previous disturbance:

Nil

Soil weathering stage:

4 (Campbell & Claridge 1975)

Soil moisture status:

Scattered snow patches but little ablation against rock surfaces; no thaw or soil moistening

Biological activity:

Nil observed