South of Bull Pass on the old fan surface; the lower slope of a small hill with a sedimentary exposure of Pecten Fan Gravel
Altitude:
150 m
Aspect:
W
Slope:
15 °
Location Data
Observer
IBC
GGC
GPS
No
Latitude Longitude DMS
77° 31.2' S 161° 56.7' E
77° 31.2' S 161° 56.7' E
Latitude Longitude DD
-77.5200 161.9450
-77.5200 161.9450
Latitude longitude precision DD
0.0008 0.0008
0.0008 0.0008
Locality
McMurdo Dry Valley region; Wright Valley
Survey
USGS 1:50,000 Antarctic Topo. Ser. Lake Vanda Quadrangle
Climate
Soil climate zone:
Coastal Mountain
Estimated mean annual temperature:
-23
°C
Frozen ground depth:
0 cm
Frozen type:
Frozen comment:
Geology
Geological setting:
The Pecten Gravel deposit was once thought to be a glacial till from an early up valley ice advance but is now thought to represent the deposits formed prior to uplift when Wright Valley was a fjord; the sediments at the site are varied and include fine gravel; sands and shelly sand with drop-stones
Patterned ground:
Nil
Surface weathering or surface features:
Deposit overlain by undifferentiated gravels
Soil
Soil parent material:
Undifferentiated gravels over gravel, sandy, silty and shelly sediment
Previous disturbance:
Previous glaciological investigations at the site
Soil weathering stage:
Soil moisture status:
Surface is snow free; no soil moistening observed
Biological activity:
Nil observed
Profile Description
Horizon
Depth
Description
370a
olive yellow (5Y 6/6) sandy to granular silt; lenzoid; particles rounded to subrounded; unstained,
370b
olive (5Y 4/4) pebbly gravel; loose; rock particles rounded to subangular; unstained,
370c
pale olive (5Y 6/2) shelly gravelly silty sand; firmly cohesive; rock particles subangular to rounded and unstained,
370d
olive (5Y 5/4) sandy pebbly gravel; loose; rock particles subrounded to subangular and non to weakly stained,