314

Site number:

314

Authors:

IBC, GGC

Date recorded:

1972/11/20

Reason Sampled:

Soil weathering examination

Description:

On the SE side of Lake Bonney, approximately 1.3km S of the NE end of the lake, on a bench surface which is devoid of a till cover; the surface is an undulating bedrock surface with scattered large erratics; the soil site is on weathered granite bedrock

Altitude:

350 m

Aspect:

W

Slope:

20 °

Climate

Soil climate zone:

Central Mountain

Estimated mean annual temperature:

-23 °C

Frozen ground depth:

36 > cm

Frozen type:

Dry frozen bedrock

Frozen comment:

>36cm

Geology

Geological setting:

The granite bedrock surface, cut by occasional dolerite dykes, is undulating with minor till remnants but numerous large (up to 5m) granite erratics; the surface has probably been exposed after retreat of the local alpine glaciers which appear to have carried little debris; the surface is old judged by the cavernously weathered erratics and also bedrock weathering and disaggregation in places

Patterned ground:

Nil

Surface weathering or surface features:

Surface boulders show moderate cavernous weathering with some accompanying bedrock wind-scoop excavation; bedrock is mainly unweathered but in a few places is disaggregated to 36cm depth; smaller surface clasts are mainly harder dolerite pebbles

Soil

Soil parent material:

Disaggregated in situ granitic bedrock

Previous disturbance:

Nil

Soil weathering stage:

6 3 (Campbell & Claridge 1975)

Soil moisture status:

A dry site with no snow nearby snow patches

Biological activity:

Nil observed