488

Site number:

488

Authors:

IBC, GGC

Date recorded:

1983/01/07

Reason Sampled:

Permafrost weathering examination

Description:

2 km N of Mt Brooke on the floor of an old undulating glacially eroded valley; the surface is uneven with a broad hummock and swale topography with small scattered snowbanks; the site was in a patterned ground crack

Altitude:

2200 m

Aspect:

Nil

Slope:

0 °

Climate

Soil climate zone:

Central mountain

Estimated mean annual temperature:

-32 °C

Frozen ground depth:

20 cm

Frozen type:

Hard ice-cemented;(sampl thawed,high ice pct lost)

Frozen comment:

20cm

Geology

Geological setting:

Outcropping rocks on Mt Brooke and adjacent hills include Jurassic tuffs and lavas, Ferrar Dolerite and Beacon Group sediments; the drift mantle on the valley floor is continuous but appears to vary in weathering and age from place to place; local age variations may result from differential ablation

Patterned ground:

Moderately developed broad nets with 50cm deep troughs

Surface weathering or surface features:

Surface boulders <30cm and are mainly dolerite; rock surfaces are moderately oxidised and stained with coarser rocks showing some exfoliation and finer grained rocks some slight surface pitting; some rounding due to wind abrasion; moderately developed pebble pavement

Soil

Soil parent material:

Till derived from dolerite, tuff and sandstones

Previous disturbance:

Nil

Soil weathering stage:

6 2 (Campbell & Claridge 1975)

Soil moisture status:

Xerous, recent widespread snowfall but negligible thawing

Biological activity:

Nil observed