Permafrost and soil moisture examinations; investigation of moisture differences at a patterned ground crack
Description:
Approximately 4.5km NW of Marble Point peninsula and W of the Marble Point Air Facility; about 100m from the Wilson Piedmont Glacier; on a surface about 1m from a small thawing snow patch; in the center of a patterned ground crack; a gently sloping surface, half way between a knoll crest and a pond at the foot of the slope
Altitude:
70 m
Aspect:
N
Slope:
2 °
Location Data
Observer
IBC
GGC
GPS
Yes
Latitude Longitude DMS
77° 24.94' S 163° 39.78' E
77° 25.1' S 163° 0.0' E
Latitude Longitude DD
-77.41570 163.66300
-77.4183 163.000
Latitude longitude precision DD
0.00008 0.00008
0.0008 0.008
Locality
Marble Point, western McMurdo Sound
Survey
USGS Antarctica Topographic Series 1:50,000; Marble Point, Antarctica
Climate
Soil climate zone:
Coastal Antarctic
Site temperature profile
Depth (cm)
Soil temp (°C)
Notes
167
-12.9
Estimated mean annual temperature:
-18
°C
Frozen ground depth:
18 cm
Frozen type:
Hard ice-cemented
Frozen comment:
18cm
Geology
Geological setting:
The surface is a gently undulating till plain formed by retreat of the Wilson Piedmont Glacier; the Marble Point region is an old landscape, with deposits of phillipsite, buried soils and oxidised gneiss, which have been covered by advances of the grounded Ross Ice Shelf; later ice retreat and glaciological features have been controlled by changes in the stranded Wilson Piedmont Glacier; the till mantle is patchy and dominated largely by locally occurring rocks; granodiorite, granite, marble, gneiss, and dolerite
Patterned ground:
Weakly developed 20m nets; 5cm troughs with active open cracks
Surface weathering or surface features:
Most boulders angular and unstained; a few with distinct oxide staining; a moderately developed pebble and cobble pavement; calcium carbonate coatings beneath many surface clasts; some surface salt efflorescences adjacent to thawing snow patches
Soil
Soil parent material:
Bouldery sandy gravel till
Previous disturbance:
Extensive mechanical and human activity in the region since the mid-1950's
Dry at the edge of the patterned ground crack; no indication of an underlying ice wedge
Biological activity:
Nil at site; moss patches and cyanobacteria are common locally
Profile Description
Horizon
Depth
Description
616a
-2
–
0
cm
surface granular to bouldery gravel; rock particles dominantly subangular and unstained but some weakly oxidised,
616b
0
–
3
cm
light yellowish brown (2.5Y 6/4) sandy gravel; loose; a few small cyanobacterial particles; rock particles subangular and unstained; distinct boundary,
616c
3
–
18
cm
light yellowish brown (2.5Y 6/4) sandy gravel; loose to weakly cohesisve; slightly moist; rock particles subangular and unstained; distinct boundary,
616d
18
–
32
cm
pale olive (5Y 6/4) sandy to silty gravel; firmly frosted; rock particles angular to subangular and unstained; sharp boundary,
616e
37
–
48
cm
drill core; pale olive (5Y 6/3) sandy to silty gravel; rock particles subangular and unstained,
616f
48
–
56
cm
drill core; pale olive (5Y 6/3) sandy to silty gravel; rock particles subangular and unstained,
616g
56
–
67
cm
drill core; pale olive (5Y 6/3) sandy to silty gravel; rock particles subangular and unstained,
616h
67
–
93
cm
drill core; light grey (5Y 7/3) sandy to silty gravel; rock particles subangular and unstained,
616i
93
–
104
cm
drill core; pale olive (5Y 6/3) sandy to silty gravel; rock particles subangular and unstained,
616j
104
–
120
cm
drill core; pale olive (5Y 6/3) sandy to silty gravel; rock particles subangular and unstained,
616k
120
–
141
cm
drill core; pale olive (5Y 6/3) sandy to silty gravel; rock particles subangular and unstained,
616l
141
–
167
cm
drill core; pale olive (5Y 6/3) sandy to silty gravel; rock particles subangular and unstained