Long Term Ecological Research (nematode experimental area) site investigation of soil properties; this site (LTER 6) is adjacent to Elevational Transect C 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:
Near the Northwest corner of LTM elevational transect C plot, on an elongated prominent bench or terrace surface, about 125m above Lake Hoare; about 20m from the northern edge of the bench; the bench surface has well marked patterned ground and rises southwards merging into slope deposits from the north face of Andrews Ridge; some slight deflation around upstanding boulders; this site is designated LTER 6b and was immediately alongside LTER 6a
Altitude:
175 m
Aspect:
N
Slope:
3 °
Location Data
Observer
IBC
GPS
Yes
Latitude Longitude DMS
77° 38.27' S 162° 53.22' E
Latitude Longitude DD
-77.63780 162.88700
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;
Site temperature profile
Depth (cm)
Soil temp (°C)
Notes
1
9.8
5
5.5
15
-0.2
33
-2.4
Estimated mean annual temperature:
-21
°C
Frozen ground depth:
33 cm
Frozen type:
Hard ice-cemented
Frozen comment:
33cm
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 till is probably older than that at lower altitude closer to the lake and may be very slightly more oxidised
Patterned ground:
Uneven active net 15m across 75cm wide with 30cm deep trough
Surface weathering or surface features:
Some weak surface staining, pitting and polish nil and some weak ventifaction; rounding generally weak but stronger on upstanding boulders; carbonate coatings on undersides of surface clasts
Soil
Soil parent material:
Pred. granite (45% up to 1.3m), gneiss/schist (30% up to 60cm), sandy gravel with silt incr. with depth; minor amounts of dolerite (10% up to 40cm), dyke rock (5% up to 12cm), volcanic scoria (1% up to 3cm), sandstone (2% up to 20cm) and occ. marble
Previous disturbance:
Possible light treading associated with the adjacent LTM monitoring site
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
873a
-2
–
0
cm
surface pebbles (30%), cobbles (10%) granules and sand (30%) with some boulders (10%); weakly stained; coarser clasts subangular to subrounded with smaller particles mainly rounded to subrounded; carbonate coatings beneath larger clasts; some thin soluble salts beneath a few dark coloured clasts;
873b
0
–
2
cm
light olive grey (5Y 6/2) gravelly sand (<2mm 52%); loose; carbonate coatings beneath some larger clasts; some weak surface staining; rock particles mainly subangular with rounding ofd some smaller particles; diffuse boundary,
873c
2
–
15
cm
light olive grey (5Y 6/2) gravelly sand (<2mm 49%); loose; carbonate coatings beneath some larger clasts; rock particles unstained and mainly subangular; distinct boundary,
873d
15
–
25
cm
light olive grey (5Y 6/2) gravelly silty sand; moderately cohesive; weakly developed vesicular structure; carbonate coatings around some clasts; rock particles unstained and subangular; distinct boundary,
873e
25
–
30
cm
light olive grey (5Y 6/2) gravelly silty sand; firmly cohesive; weakly developed vesicular structure; rock particles unstained and dominantly subangular; sharp boundary,
873f
30
–
37
cm
light olive grey (5Y 6/2) gravelly sand; very hard; ice-cemented; rock particles unstained and dominantly subangular