530

Site number:

530

Authors:

IBC, GGC

Date recorded:

1988/01/06

Reason Sampled:

Soil weathering examination

Description:

Central Alatna Valley, approximately 10km NNE of Battleship Promontory; 500m from the southern edge of the stagnant Staten Island Heights glacier; on an undulating moraine surface

Altitude:

1000 m

Aspect:

Nil

Slope:

0 °

Climate

Soil climate zone:

Coastal Mountain, xerous to subxerous

Estimated mean annual temperature:

-25 °C

Frozen ground depth:

28 cm

Frozen type:

Hard ice-cemented

Frozen comment:

28

Geology

Geological setting:

Alatna Valley has formed through ice recession from the Benson Glacier and ice from Staten Island Heights; the local rocks are extensive Beacon Sandstone outcrops capped with Ferrar Dolerite; granite outliers are also present; the presence of pink Irizar Granite indicates earlier up-valley ice movement; soil ages may be complicated the rate at which local ice masses have retreated

Patterned ground:

Moderately developed broad nets; some active cracks up to 50cm deep

Surface weathering or surface features:

Dolerite clasts strongly stained on lee sides but abraded on up-wind sides; oxidised faces with distinct weathering rhinds; some exfoliation of weathering rhinds; most clasts subrounded; weakly to moderately formed cobble to boulder pavement with some ventiforms; salts beneath some surface clasts; some wind ripples on flat lying rock surfaces

Soil

Soil parent material:

Sandy till from dolerite, granite and sandstone

Previous disturbance:

Nil

Soil weathering stage:

6 4 (Campbell & Claridge 1975)

Soil moisture status:

Some snow in the patterned ground cracks; recent light snow fall but negligible soil moistening

Biological activity:

Nil observed