721

Site number:

721

Authors:

IBC,GGC,MRB,DIC

Date recorded:

1993/12/30

Reason Sampled:

Soil moisture, permafrost monitoring and soil climate measurement

Description:

A gently sloping area forming a small bench on a moderately steep slope between Crater Hill and the east coast of Ross Island, approximately 150m northwest from the Scott base buildings; drill hole and access tube site located in the southern undisturbed part of an experimental area and near the edge of a small patch of snow

Altitude:

75 m

Aspect:

SE

Slope:

7 °

Climate

Soil climate zone:

Coastal mountain

Estimated mean annual temperature:

-18 °C

Frozen ground depth:

36 cm

Frozen type:

Hard frozen and ice cemented with segregated ice

Frozen comment:

36cm

Geology

Geological setting:

The deposit comprises volcanics of the McMurdo Volcanics Formation mainly as scoriaceous flows; the surface materials are a thin cover of mainly fractured bedrock with addition of glacially derived granular and pebble clasts from outside the immediate area; the volcanic bedrock has been considerably fractured by freeze thaw; the surface age is probably very late Pleistocene (Ross Sea Glaciation) having been modified by McMurdo Sound filling glacial ice

Patterned ground:

Weakly developed and without distinctive trough expression or well developed net pattern

Surface weathering or surface features:

Surface boulder clasts show some slight wind polish but no surface oxidation; pavement between larger clasts is dominantly granular-pebble sized; some thin surface salt accumulations occur near wet patches formed by snow melt

Soil

Soil parent material:

Fragmented bouldery volcanic bedrock with some additions of glaciogenic finer materials, in part with some modification by slope drift processes

Previous disturbance:

No evidence of past mechanical disturbance at the immediate trial site area but moderate foot traffic disturbance is very likely; present disturbance includes the presence of numerous particles of introduced organic and inorganic materials

Soil weathering stage:

6 1 (Campbell & Claridge 1975)

Soil moisture status:

Xerous to subxerous; soil is moist below the surface; some moisture derived from small local transient snow banks

Biological activity:

A few small patches of yellow lichen and some moss in the general vicinity