Comparison of a soil outside the Lake Hoare LTER experimental area and with a different topographic setting with those at the LTER site
Description:
Approximately 1.2k south of Lake Hoare on the crest of the sloping ridge surface; a broad undulating ridge surface with minor knolls; the site is near the ridge crest
Altitude:
390 m
Aspect:
NE
Slope:
9 °
Location Data
Observer
IBC
GPS
Yes
Latitude Longitude DMS
77° 38.56' S 162° 53.76' E
Latitude Longitude DD
-77.64270 162.89600
Latitude longitude precision DD
0.00008 0.00008
Locality
Near Lake Hoare, Taylor Valley, McMurdo Dry Valley region, Transantarctic Mountains; at the eastern end of Andrews Ridge
Survey
Lake Bonney Quadrangle, Antarctic 1:50,000 Topographic Series, USGS 1975
Climate
Soil climate zone:
Coastal mountain;
Site temperature profile
Depth (cm)
Soil temp (°C)
Notes
1
5.6
5
2.8
22
-3.3
55
-5.1
Estimated mean annual temperature:
-23
°C
Frozen ground depth:
55 cm
Frozen type:
Hard ice-cemented
Frozen comment:
55cm
Geology
Geological setting:
Bedrock (granite, schist/gneiss, dolerite) outcrops on the ridge in places but the ridge is mostly covered with till; the till appears older than Ross I but younger tills including Ross I may overlie the older deposits; the lithology appears to be extremely variable; at the sample site, younger (Ross I till) appears to overlie older till, perhaps equivalent to weathering stage II
Patterned ground:
Weakly developed net, 15m diameter with 55cm wide troughs 20cm deep
Surface weathering or surface features:
A well developed pebble pavement with weak staining on some clasts; moderate to strong exfoliation on some clasts (older till remnants?); moderate ventiforms and rounding with some weak polish; weakly developed carbonate coatings and some diffuse white salts under a few clasts
Soil
Soil parent material:
Mixed lithology sandy gravel till (dolerite 20%, granite 15% gneissic 15% volcanic scoria 15% sandstone) with clasts 25-60mm, over sandy silty gravel older till; the lower till has less basaltic material
Previous disturbance:
Some old footprinting and soil pit examination sites in the general vicinity but nil observed at the site
Xerous to subxerous; a dry site with no adjacent snow patches
Biological activity:
Nil observed
Profile Description
Horizon
Depth
Description
874a
-2 – 0 cm
surface pebbles, cobbles, granules and sand (>2mm 38% <2mm 62%), some clasts with moderately oxidised surfaces; a few white salts beneath some clasts and few carbonate coatings; clasts subangular to subrounded; diffuse boundary,
874b
0 – 2 cm
light olive grey (5Y 6/2) gravelly sand (>2mm 38% <2mm 62%); loose to weakly cohesive; weakly developed vesicular structure; many fine distinct white salt precipitations dominantly on stone undersides; rock particles subangular to rounded; diffuse boundary,
874c
2 – 10 cm
light olive grey (5Y 6/2) gravelly sand (>2mm 38% <2mm 62%); loose; many fine distinct white salt precipitations beneath clasts; rock particles unstained and subangular to rounded; sharp irregular boundary,
874d
10 – 22 cm
pale olive grey (5Y 6/3) gravelly silty sand (>2mm 21% <2mm 79%); weakly to moderately cohesive; rock particles unstained and subangular; diffuse boundary,
874e
22 – 40 cm
pale olive grey (5Y 6/3) cobbly gravelly silty sand (>2mm 21% <2mm 79%); moderately cohesive; rock particles unstained and dominantly subangular to subrounded; diffuse boundary,
874f
40 – 55 cm
pale olive grey (5Y 6/3) cobbly to bouldery gravelly sand; moderately cohesive; rock particles unstained and dominantly subangular to subrounded; sharp boundary,
874g
55 – 57 cm
pale olive (5Y 6/3) sandy gravel; very hard; ice-cemented, on hard ice-cemented ground