Site Information

Site number:
891
Authors:
IBC
Date recorded:
1999/12/09
Reason Sampled:
Long Term Ecological Research (nematode experimental area) site investigation of soil properties; this site (LTER 8) was chosen for repeat sampling every 3-4 days to see if there were measurable changes in soil moisture with time
Description:
About 1.4km SSE of Camp Hoare; 5m north of the LTM Decomposition plot, about 300m south of Lake Hoare among shallow ridge and gully topography on the lower part of the valley side; the site is to the east of a low ridge and in a 30m wide hollow on a sloping hillside; it has an uneven slightly hummocky surface; this is the third sampling at this site and is designated LTER 8c
Altitude:
100 m
Aspect:
NNE
Slope:
5 °
Location Data
Observer IBC
GPS Yes
Latitude Longitude DMS 77° 38.10' S 162° 52.50' E
Latitude Longitude DD -77.6350 162.8750
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
Site temperature profile
Depth (cm)Soil temp (°C)Notes
23 0
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:
Moderately developed 20m irregular net with 20cm deep troughs, 50cm wide
Surface weathering or surface features:
Very weak surface staining on some clasts with no pitting, exfoliation or polish; weak ventifaction on some clasts and moderate rounding; calcium carbonate coatings on undersides of many clasts

Soil

Soil parent material:
Sandy to silty gravel with the coarse fraction consisting of granite (60%) and gneiss (20%) and dolerite (10%) with minor sandstone (8%) volcanic (scoria 1%) 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; surface dry 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
HorizonDepthDescription
891a -2 – 0 cm cobbly sandy gravel (<2mm 35% >2mm 65%); loose; rock particles unweathered with larger particles subrounded; abundant calcium carbonate coatings beneath surface clasts; indistinct boundary,
891b 0 – 2 cm light olive grey to pale olive (5Y 6/2 - 6/3) gravelly sand (<2mm 62% >2mm 38%); loose to weakly cohesive with well developed vesicular structure; rock particles unweathered with larger rock particles subangular and smaller particles subrounded; many carbonate coatings; diffuse boundary,
891c 2 – 15 cm light olive grey (5Y 6/2) cobbly gravelly silty sand (<2mm% 62% <2mm% 38%); weakly cohesive with well developed vesicular structure; rock particles unweathered and subangular to subrounded; carbonate coatings around many clasts; sharp boundary,
891d 15 – 25 cm light olive grey to olive grey (5Y 6/2 - 5/2) gravelly sand (2mm% 80% >2mm 20%); moderately cohesive and moist; unweathered with rock particles subangular to subrounded; many carbonate coatings; distinct boundary,
891e 25 – 32 cm light olive grey to olive grey (5Y 6/2 - 5/2) gravelly silty sand; firmly cohesive and frosted; rock particles unweathered and subangular to subrounded; many carbonate coatings; sharp boundary,
891f 32 – 39 cm light olive grey to olive grey (5Y 6/2 - 5/2) gravelly sandy silt; very hard; ice-cemented; rock particles unweathered and subangular to subrounded

Sample Data

Physical Data
Sample nameDepth descriptionTop (cm)Base (cm)Bulk DensityDry Bulk DensityGravimetric MoistureVol. Moisture (BD=2)
891a 2-0cm -2.0 0.0 2.03 0.12
891b 0-2cm 0.0 2.0 1.84 0.21
891c 2-15cm 2.0 15.0 1.84 0.85
891d 15-25cm 15.0 25.0 1.4 5.31
891e 25-32cm 25.0 32.0 1.31 4.85
891f 32-39cm 32.0 39.0 nd 5.67
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
891a 48.0
891b 79.0
891c 86.0
891d 83.0
891e 79.0
891f 81.0

Photos

Photo record:
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