Site Information

Site number:
802
Authors:
IBC, GGC
Date recorded:
1995/01/12
Reason Sampled:
Permafrost and soil moisture investigations
Description:
Approximately 2.4km NNE of Mt Brooke on the floor of a valley; the site is on the crest of a small moraine knoll on the undulating surface of the valley floor, about 300m SW of site 801
Altitude:
2015 m
Aspect:
Nil
Slope:
0 °
Location Data
Observer GGC IBC
GPS No
Latitude Longitude DMS 76° 48.5' S 159° 54.7' E 76° 48.9' S 159° 54.5' E
Latitude Longitude DD -76.808 159.9117 -76.8150 159.908
Latitude longitude precision DD 0.004 0.0008 0.0008 0.004
Locality Coombs Hills, northern Dry Valley region and to the north of Mt Brooke
Survey not recorded

Climate

Soil climate zone:
Central Mountain
Estimated mean annual temperature:
-32 °C
Frozen ground depth:
0 cm
Frozen type:
dry frozen
Frozen comment:

Geology

Geological setting:
Rocks of the area are dominantly volcanic (doleritic but dark coloured, fine grained and with a somewhat vesicular form compared with usual dolerite) and softer 'haloclastite', (earlier described as tillite); the haloclastite contains basement rocks, dolerite and sandstone clasts with sedimentary structures in places; it is softer and more erodible than the dolerite; the till cover across the area is quite variable and is generally thinner towards Mt Brooke and towards the higher ridges; the till mantle has formed an undulating ridge and swale surface across the landscape with a mega- ripple appearance, which may relate to the manner in which the ice sheets have retreated and ablated, rather than to subsequent landscape modification by wind; although the land surface has a mega ripple, low dune-like surface, the deposits have no dune like characteristics
Patterned ground:
Nil at site
Surface weathering or surface features:
Cobbly to bouldery surface with a weakly developed pavement; coarse grained dolerite strongly stained and fine grained dark dolerite unstained but moderately polished; slight surface rounding and weakly ventiform; some rocks pitted and some showing disaggregation

Soil

Soil parent material:
Dominantly dolerite/volcanic till but with the fine fraction from the more erodible haloclastite; partly crumbled dolerite/volcanic bouldery till
Previous disturbance:
Nil
Soil weathering stage:
6 4 (Campbell & Claridge 1975)
Soil moisture status:
Xerous; several snowfalls and a recent fall within 12 hours which produced 7mm of snow with approximately .68mm of water; most ablated with little sign of soil moistening
Biological activity:
Nil observed at site
Profile Description
HorizonDepthDescription
802a -4 – 0 cm surface cobbles, pebbles and boulders; subangular to subrounded; weakly stained,
802b 0 – 2 cm reddish brown to brown (5YR 5/4 - 7.5YR 5/4) cobbly gravelly sand; loose; few fine salt flecks and some accumulations beneath surface stones; rock particles subangular and non to weakly stained with some moderately altered; distinct boundary,
802c 2 – 14 cm yellowish brown (10YR 5/4) cobbly to pebbly gravel; weakly to moderately cohesive; abundant salt accumulations especially around some clasts; rock particles mainly subangular and unstained but oxidation ghosts around some clasts; distinct boundary,
802d 14 – 30 cm light yellowish brown (10YR 6/4) very stony cobble, pebble and boulder gravel; weakly cohesive; scattered salts; rock particles angular and unstained; indistinct boundary,
802e 30 – 50 cm light yellowish brown (10YR 6/4) very stony pebble and cobble gravel; weakly cohesive; some scattered salts; rock particles angular to subangular and unstained; indistinct boundary,
802f 50 – 70 cm light yellowish brown (10YR 6/4) very stony pebble and cobble gravel; weakly cohesive; some scattered salts; rock particles angular to subangular and unstained; indistinct boundary,
802g 70 – 90 cm light yellowish brown (10YR 6/4) very stony pebble and cobble gravel; weakly cohesive; some scattered salts; rock particles angular to subangular and unstained; indistinct boundary,
802h 90 – 110 cm light yellowish brown (10YR 6/4) stony gravel; loose; rock particles angular to subangular and unstained,

Sample Data

Physical Data
Sample nameDepth descriptionTop (cm)Base (cm)Bulk DensityDry Bulk DensityGravimetric MoistureVol. Moisture (BD=2)
802a 4-0 -4 0 1.06
802b 0-2 0 2 1.39 1.92
802c 2-14 2 14 1.43 3.41
802d 14-30 14 30 1.53 3.39
802e 30-50 30 50 1.45 2.64
802f 50-70 50 70 1.52 2.82
802g 70-90 70 90 1.52 2.66
802h 90-110 90 110 1.51 3.62
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
802a 10.4
802b 57.3
802c 45.38
802d 25.63
802e 12.89
802f 15.48
802g 13.61
802h 35.95
Clay Mineralogy
Sample nameMicaIHMHIV - IHMICHLVTHIVCHLSMCHL SMFE - CHLHTQTZFLDHBCALNotes
802a :
802b :
802c :
802d :
802e :
802f :
802g :
802h :

Photos

Photo record:
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