Northern end of the La Gorce Mountains on a low moraine covered surface at the north end of Ackerman Ridge, on the east side of Scott Glacier; the surface is undulating, low and patterned ground covered and the sample site was at the centere of a polygon
Altitude:
1750 m
Aspect:
W
Slope:
4 °
Location Data
Observer
IBC
GGC
GPS
No
Latitude Longitude DMS
86° 32.5' S 148° 20' W
86° 32.5' S 148° 20' W
Latitude Longitude DD
-86.542 -148.33
-86.542 -148.33
Latitude longitude precision DD
0.004 0.08
0.004 0.08
Locality
Scott Glacier region, southern Trans-antarctic Mountains on Ackerman Ridge
Survey
US Geological Survey 1:250 000, 1968, Mount Blackburn
Climate
Soil climate zone:
Inland Mountain
Estimated mean annual temperature:
-38
°C
Frozen ground depth:
0 cm
Frozen type:
Stagnant glacial ice
Frozen comment:
Geology
Geological setting:
The ground surface is ablation till underlain by stagnant ice from the Robert Scott Glacier; the till shows a gradual progression from the Scott Glacier surface consisting of bare ice, ice with scattered clasts, a thin continuous till cover, a thicker till cover with micro undulations and incipient patterned ground cracks, increased till thickness and increased expression of hummocky ground and polygonal patterns. This development of patterned ground appears to be a function of thermal expansion/contraction processes in the stagnant glacial ice and as the cracks develop, sorting of material takes place along with infilling of the cracks with finer detritus. Surfaces such as these give strong indications of relatively recent glacial retreat. This sample was collcted from icy material below the mineral soil to confirm that rock material in the ice was similar to that at the ground surface and therefore ablating from the ice
Patterned ground:
Polygons up to 4m across with snow filled troughs
Surface weathering or surface features:
Angular unstained clasts with little pavement development
Soil
Soil parent material:
Ice and rubble from patterned ground
Previous disturbance:
Nil
Soil weathering stage:
6
Soil moisture status:
Ultraxerous; snow in adjacent patterned ground cracks