Long Term Ecological Research (nematode experimental area) site investigation of soil properties; this site (LTER 9) was selected for repeat sampling to measure changes in soil moisture
Description:
Adjacent to the westernmost plot, approximately 225m from Lake Hoare; the site is on the floor of an elongated depression between two low moraine ridges and is 2m to the north of the LTM Algae plot; the surface is slightly concave and is moderately bouldery; this site is immediately adjacent to LTER 9c and designated LTER 9d
Altitude:
75 m
Aspect:
NE
Slope:
3 °
Location Data
Observer
IBC
GPS
Yes
Latitude Longitude DMS
77° 38.10' S 162° 53.10' E
Latitude Longitude DD
-77.6350 162.8850
Latitude longitude precision DD
0.0008 0.0008
Locality
Near Lake Hoare, Taylor Valley, McMurdo Dry Valley region, Transantarctic Mountains
Survey
Lake Bonney Quadrangle, Antarctic 1:50,000 Topographic Series, USGS 1975
Climate
Soil climate zone:
Coastal mountain;
Estimated mean annual temperature:
-20
°C
Frozen ground depth:
32 cm
Frozen type:
Hard ice-cemented
Frozen comment:
32cm
Geology
Geological setting:
The deposit is unweathered Ross I till, possibly derived from the Canada Glacier but almost certainly with an up-valley influence because of the presence of marble clasts from basement rocks; the tills may be fluvio-glacial owing to complex depositional ice-marginal processes as the sand % generally increases downwards while there are noticeably more coarse clasts at the surface
Patterned ground:
Irregular net 20m across with trough 1m wide and 20cm deep
Surface weathering or surface features:
Distinct (slight) surface staining on some clasts; also weak exfoliation on a few granite clasts and some weak ventifaction and nil polish; clasts are generally subrounded to subangular; carbonate coatings occur beneath some surface clasts
Soil
Soil parent material:
Predominantly granite (65%), dolerite (10%) with minor schist, sandstone, marble and scoria; bouldery sandy gravel becoming finer (silty) at depth
Previous disturbance:
Site probably disturbed by foot traffic activity during biological research activities near the site
Xerous to subxerous; surface slightly moist from snowfall at the time of sampling
Biological activity:
Nil observed at site, nematodes present in adjacent soil; some green algae beneath marble clasts in the general area
Profile Description
Horizon
Depth
Description
908a
-2 – 0 cm
surface pebbles, cobbles and boulders; loose; weakly developed pavement; some slight surface staining; clasts subangular to subrounded; carbonate coatings around some clasts; a few fine white salt flecks; diffuse boundary,
908g
0 – 2 cm
pale olive (5Y 6/3) sandy gravel,
908i
0 – 2 cm
pale olive (5Y 6/3) sandy gravel with salt flecks,
908b
0 – 2 cm
pale olive (5Y 6/3) pebbly to bouldery sandy gravel; loose; well developed vesicular structure; rock particles subangular to subrounded with some weak staining; many carbonate coatings; diffuse boundary
908c
2 – 15 cm
diffuse boundary,; pale olive (5Y 6/3) pebbly to bouldery sandy gravel; weakly cohesive; weakly developed vesicular structure; rock particles subangular to subrounded with larger clasts angular; carbonate coatings around many clasts
908h
2 – 5 cm
pale olive (5Y 6/3) sandy gravel, sampled on a nearby surface where the snow fall immediately thawed
908j
2 – 5 cm
pale olive (5Y 6/3) sandy gravel with salt flecks,
908d
15 – 25 cm
pale olive (5Y 6/3) cobbly silty gravel; moderately cohesive; moderately developed vesicular structure; rock particles mainly subangular to angular; sharp boundary,
908e
25 – 33 cm
pale olive (5Y 6/3) pebbly sandy silt; firmly cohesive and frosted; moderately developed vesicular structure; rock particles subangular; sharp boundary;
908f
33 – 38 cm
pale olive (5Y 6/3) sandy silt; very hard, ice-cemented, on ice-cemented ground, sampled from nearby surface with a thin snow cover;