Site Information

Site number:
912
Authors:
IBC
Date recorded:
1999/12/14
Reason Sampled:
Long Term Ecological Research (nematode experimental area) site investigation of soil properties; this site (LTER 4) was selected for repeat sampling to measure changes in soil moisture adjacent to a retreating snow bank; the snow patch adjacent to the sampling transect had completely thawed by sample day 15
Description:
North side of the LTM Datalogger plot, approximately 100m south of Lake Hoare, on the lower slope of a shallow gully which forms part of an undulating ridge and gully/basin topography; the site is a fine gravelly toe slope surface and is immediately adjacent to a snow patch which was retreating; this site is approximately 25m to the east of LTER 1
Altitude:
90 m
Aspect:
N
Slope:
2 °
Location Data
Observer IBC
GPS Yes
Latitude Longitude DMS 77° 37.99' S 162° 52.92' E
Latitude Longitude DD -77.63320 162.88200
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:
-20 °C
Frozen ground depth:
0 Nd
Frozen type:
Nd
Frozen comment:
Nd

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:
Weakly developed 15m net with 30cm trough width, 10cm deep
Surface weathering or surface features:
A pebble pavement surface with few weathering features

Soil

Soil parent material:
Predominantly granite/gneiss/schist sandy gravel with minor amounts of dolerite, volcanic (scoria), sandstone and marble
Previous disturbance:
Site probably disturbed by foot traffic activity during biological research activities near the site
Soil weathering stage:
6 1 (Campbell & Claridge 1975)
Soil moisture status:
Xerous to subxerous; a moist site; the snow patch adjacent to the sampling transect had completely thawed but a moist soil fringe was still present
Biological activity:
Nil observed at site, nematodes present in adjacent soil; some green algae beneath marble clasts in the general area
Profile Description
HorizonDepthDescription
912a 0 – 2 cm light olive grey to pale olive (5Y 6/2 - 6/3) pebbly sandy gravel; loose to weakly cohesive; moist; rock particles subangular to subrounded; some carbonate coatings; diffuse boundary,
912b 2 – 5 cm light olive grey to pale olive (5Y 6/2 - 6/3) pebbly sandy gravel; loose to weakly cohesive; moist; rock particles subangular to subrounded; some carbonate coatings; diffuse boundary
912c 5 – 13 cm
912d 13 – 18 cm

Sample Data

Physical Data
Sample nameDepth descriptionTop (cm)Base (cm)Bulk DensityDry Bulk DensityGravimetric MoistureVol. Moisture (BD=2)
912a 0-2cm 0.0 2.0 1.7 0.63
912b 2-5cm 2.0 5.0 1.52 1.84
912c 5-13cm 5.0 13.0 1.49 3.3
912d 13-18cm 13.0 18.0 1.59 4.41
Particle size distribution
Sample name< 2 mm2 - 0.5 mm0.5 - 0.25 mm0.25 - 0.1 mm0.1 - 0.05 mm0.05 - 0.02 mm0.02 - 0.002 mm< 0.002 mmFe2O3CaCO3Notes
912a 67.0
912b 68.0
912c 71.0
912d 79.0

Photos

Photo record:
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