675

Site number:

675

Authors:

IBC, GGC

Date recorded:

1992/12/23

Reason Sampled:

assessment of environmental impacts from past human activities at Vanda Station

Description:

the upper surface of a greywater disposal site, 50m ES of the main Vanda Station building; the site is on the upper surface of a shallow, 4m deep gully and is on the edge of a lamprophyre dyke;

Altitude:

93 m

Aspect:

SE

Slope:

8 °

Climate

Soil climate zone:

central mountain

Estimated mean annual temperature:

-20 °C

Frozen ground depth:

35 ~ cm

Frozen type:

dry frozen

Frozen comment:

~35cm

Geology

Geological setting:

the rocks of the area are granodiorites that have been cut with lamprophyre dykes and form a strongly undulating ridge and gully topography as a result of ice over riding from down-valley and up-valley glaciations and to a lesser extent, subaerial weathering; cryogenic weathering, probably assisted by repeated past rises and falls of waters in Lake Vanda, has generally given rise to a heavily fractured upper bedrock surface with common angular platy boulders; sands, derived partly from sorted lake sediments and also from aerial erosion fill most of the rock fracture interstices

Patterned ground:

Surface weathering or surface features:

some finer textured surface dyke rocks are abraded with distinctive ventiforms; coarser granodioritic clasts are crumbling by granular disintegration

Soil

Soil parent material:

coarse fraction is lamprophyre dyke rocks with quartz/feldspar sand filling the interstices; some organic material from domestic sources

Previous disturbance:

a disposal sithe of domestic waste waters

Soil weathering stage:

6 1 (Campbell & Claridge 1975)

Soil moisture status:

xerous; soil surface very occasionally moistened by summer snowfall; the soil has been wetted in the past from discharges of Vanda Station greywaters

Biological activity: