770

Site number:

770

Authors:

IBC,GGC,MRB,DIC

Date recorded:

1994/01/19

Reason Sampled:

Permafrost and soil moisture investigations for comparison with soils from moist coastal regions

Description:

On the southeast side of the valley on a higher part of the valley floor surface, an old undulating till surface about 1.7km southeast of West Beacon and 1.2km northwest of East Beacon; the site is a few metres below the crest of a shallow ridge and about 50m to the north of site 769 on a surface that forms an extensive boulder field

Altitude:

1850 m

Aspect:

NW

Slope:

6 °

Climate

Soil climate zone:

Central Mountain

Estimated mean annual temperature:

-30 °C

Frozen ground depth:

5 ~ cm

Frozen type:

dry frozen over hard ice-cemented

Frozen comment:

~ 5cm

Geology

Geological setting:

Local outcropping rocks are Ferrar Dolerite and Beacon Sandstone; the till at this site comprises predominantly dolerite and sandstone but the till has probably come from multiple glaciations with thin accessions of till; till lithology appears to represent locally derived rocks and is bouldery to cobbly

Patterned ground:

Polygons are 15m across with troughs 60cm deep and 1.2m wide

Surface weathering or surface features:

some coarse dolerite cobbles and boulders are strongly exfoliating; finer grained dolerite clasts strongly stained, polished and pitted; the pavement is weakly developed; salts occur beneath some surface stones

Soil

Soil parent material:

Bouldery to cobbly sandy gravel till derived from dolerite and sandstone; larger clasts are mainly dolerite

Previous disturbance:

Nil

Soil weathering stage:

6 3/4 (Campbell & Claridge 1975)

Soil moisture status:

Xerous; some snow falls in winter and summer months but most is lost through ablation or by blowing away; some small snow remnants occur in nearby patterned ground cracks

Biological activity:

Only endolithic algae observed below the surface of sandstone boulders or outcrops