773

Site number:

773

Authors:

IBC,GGC,MRB,DIC

Date recorded:

1994/01/20

Reason Sampled:

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

Description:

At the mouth of the valley, on the up-valley side of a low ridge forming an escarpment overlooking Taylor Glacier and 50m from the ridge crest; approximately 1.8km east-northeast of West Beacon and 2km north- northwest of East Beacon; part of a series of small moraine ridges and hollows that slope downwards in the up-valley direction; the ground surface is broad and slightly undulating with many surface boulders

Altitude:

1700 m

Aspect:

SE

Slope:

3 °

Climate

Soil climate zone:

Central Mountain

Estimated mean annual temperature:

-30 °C

Frozen ground depth:

65 cm

Frozen type:

hard ice-cemented

Frozen comment:

65

Geology

Geological setting:

Local outcropping rocks are Ferrar Dolerite and Beacon Sandstone; the till at this site differs from most of the other tills in the valley in that it contains a significant proportion of relatively fresh looking granodiorite and granite clasts ranging from large boulders to cobbles; the till is considered to have been derived from an up-valley movement of ice which deposited as ice entered and retreated from this higher altitude valley, currently some 650m above the ice level of the Upper Taylor Glacier; the nearest known granodiorite outcrops are several km down valley; pale coloured fine textured and low density material occurring as a layer may possibly be volcanic ash

Patterned ground:

Very weakly expressed but some older inactive polygon cracks

Surface weathering or surface features:

Dolerite and sandstone clasts are subrounded and strongly stained and polished; some are weakly to moderately ventiform; some granite clasts are crumbled and are cavernously weathered; the cobble and boulder pavement is well developed; salts occur beneath surface stones

Soil

Soil parent material:

Old bouldery sandy to silty gravel till derived from granodiorite, granite, dolerite and sandstone; may possibly include some volcanic ash

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 pockets of snow in patterned ground cracks

Biological activity:

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