[902] Long Term Ecological Research (nematode experimental area) site investigation of soil properties; this site (LTER 7) is adjacent to Elevational Transect B plot and was sampled at 2 to 4 day intervals to provide indications of spatial and temporal changes in soil moisture and physical properties
Description:
On the south side of Lake Hoare on the sloping valley side; on an even sloping surface just south (upslope) of LTM elevational transect B plot; adjacent ridges of bouldery till separated by a smoothly sloping pebbly surface; this site was sampled immediately adjacent to LTER 7c and is designated LTER 7d
Altitude:
130 m
Aspect:
NNW
Slope:
10 °
Location Data
Observer
IBC
GPS
Yes
Latitude Longitude DMS
77° 38.18' S 162° 53.46' E
Latitude Longitude DD
-77.63630 162.89100
Latitude longitude precision DD
0.00008 0.00008
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:
-21
°C
Frozen ground depth:
30 cm
Frozen type:
Hard ice-cemented
Frozen comment:
30cm
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 and silt % generally increase downwards; the landscape has a ridge and gully form and gullies have concentrations of finer textured deposits, possibly reflecting pro-glacial processes during ice retreat
Patterned ground:
Broad elongated weakly developed net, 25m across with trough width 65cm and depth 15cm
Surface weathering or surface features:
A well developed pebble pavement surface with no staining, pitting or exfoliation and only slight ventiforms; slight surface clast rounding
Xerous to subxerous; a 'dry' site with no adjacent snow patches
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
902a
-2
–
0
cm
surface pebbly gravel (<2mm48% >2mm 52%); loose; clasts mainly subangular with some weaak surface staining; few carbonate coatings beneath some surface clasts; sharp boundary,
902b
0
–
2
cm
light olive grey to pale olive (5Y 6/2 - 6/3) sandy gravel (<2mm 48% >2mm 52%); loose; rock particles mainly subangular with some weaak surface staining; some carbonate coatings around larger clasts; diffuse boundary,
902c
2
–
15
cm
light olive grey to pale olive (5Y 6/2 - 6/3) sandy gravel <2mm 48% >2mm 52%; loose; rock particles subangular and unstained; sharp boundary,
902d
15
–
25
cm
light olive grey (5Y 6/2) gravelly sand; firmly cohesive and frosted; rock particles subangular to subrounded and unstained; diffuse boundary,
902e
25
–
32
cm
light olive grey (5Y 6/2) gravelly sand to sand; firmly cohesive and frosted; rock particles dominantly subangular to subrounded and unstained; sharp boundary,
902f
32
–
36
cm
light olive grey (5Y 6/2) gravelly sand; very hard; ice-cemented; rock particles unstained and dominantly subangular