Approximately 2.4km NE of Mt Brooke on the eastern side of a valley on a broad ridge within the valley, about 200m above the valley floor; near a broad snow filled basis
Altitude:
2200 m
Aspect:
W
Slope:
4 °
Location Data
Observer
GGC
IBC
GPS
No
Latitude Longitude DMS
76° 48.5' S 159° 54.7' E
76° 48.3' S 159° 58.1' E
Latitude Longitude DD
-76.808 159.9117
-76.8050 159.9680
Latitude longitude precision DD
0.004 0.0008
0.0008 0.0008
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:
hard ice-cemented
Frozen comment:
ice cement at 10cm
Geology
Geological setting:
Rocks of the area are dominantly dolerite/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 an undulating 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
Patterned ground:
indistinct and weakly developed
Surface weathering or surface features:
Doleritic clasts are subrounded and weakly ventiform; some deep fine pitting on larger boulders; surface polish well developed; well developed pavement of granules, pebbles and cobbles; exfoliation or cavernous weathering is absent
Soil
Soil parent material:
Dominantly dolerite till, on ice-cemented ground near the surface, but with the fine fraction from the more erodible haloclastite; shallow till cover over ice-cemented ground
Xerous; several snowfalls but little thawing or soil moistening; a snow basin is located some 30m away
Biological activity:
nil observed at site
Profile Description
Horizon
Depth
Description
799a
-2
–
0
cm
surface pebbles, cobbles and occasional boulders; well developed pavement; rock particles subrounded and non to strongly stained; salt accumulations beneath some stones,
799b
0
–
10
cm
strong brown (7.5YR 5/8) sandy gravel; loose; rock particles subrounded and partly stained and altered; sharp boundary,
799c
15
–
27
cm
pale yellow (dry 2.5Y 7/4) gravel (drill core); hard ice- cemented ground; rock particles subangular and unstained with some partly altered,
799d
27
–
33
cm
pale yellow (dry 2.5Y 7/4) ice-cemented gravel (drill core); rock particles subangular and unstained,
799e
33
–
50
cm
pale yellow (dry 2.5Y 7/4) ice-cemented gravel (drill core); rock particles subangular and unstained; some salt accumulations in the oven-dried sample,
799f
50
–
61
cm
pale yellow (dry 2.5Y 7/4) ice-cemented gravel (drill core); rock particles subangular and unstained; some salt accumulations in the oven-dried sample,
799g
61
–
72
cm
pale yellow (dry 2.5Y 7/4) ice-cemented gravel (drill core); rock particles subangular and unstained; some salt accumulations in the oven-dried sample,
799h
72
–
80
cm
pale yellow (dry 2.5Y 7/4) ice-cemented gravel (drill core); rock particles subangular and unstained,
799i
80
–
90
cm
pale yellow (dry 2.5Y 7/4) ice-cemented gravel (drill core); rock particles subangular and unstained,
799j
90
–
104
cm
pale yellow (dry 2.5Y 7/4) ice-cemented gravel (drill core); rock particles subangular and unstained