Approximately 2.3km NNE of Mt Brooke on the floor of a valley; the site is on a flat surface, which has the appearance of a small terrace, on the undulating surface of the valley floor
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° 48.3' S 159° 54.1' E
Latitude Longitude DD
-76.808 159.9117
-76.8050 159.9020
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
Site temperature profile
Depth (cm)
Soil temp (°C)
Notes
1
-3.7
5
-5.9
10
-6.5
15
-6.8
20
-6.8
30
-6.9
40
-7.7
50
-8.6
60
-9.7
70
-10.6
80
-11.3
90
-11.6
100
-12.5
110
-13.4
120
-14.4
130
-15.5
Estimated mean annual temperature:
-32
°C
Frozen ground depth:
0 cm
Frozen type:
dry frozen
Frozen comment:
partially ice-cemented between 55-70cm
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 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:
Weakly developed non active polygons near the site
Surface weathering or surface features:
Moderately developed pebble and cobble pavement with occasional boulders; clasts non to weakly ventiform but without strong oxidation; salts beneath some surface clasts
Soil
Soil parent material:
Dominantly dolerite/volcanic till but with the fine fraction from the more erodible haloclastite
Xerous; several snowfalls and a recent fall within 12 hours also considerable drift snow; most snow cover removed by wind and ablation within 24 hours; some small semi-permanent snow patches nearby,
Biological activity:
Nil observed at site
Profile Description
Horizon
Depth
Description
803a
-3
–
0
cm
surface cobbles, pebbles and granules; subangular to subrounded and non to weakly stained,
803b
0
–
10
cm
strong brown (7.5YR 5/6) gravelly pebbly sand; loose; rock particles mainly subangular and unstained, distinct boundary
803c
10
–
20
cm
strong brown ( 7.5YR 5/6) gravelly pebbly sand; moderately cohesive; many diffuse salts; rock particles subangular and unstained; distinct boundary,
803d
20
–
55
cm
yellowish brown to brownish yellow (10YR 5/6 - 6/6) sandy pebble and cobble gravel; firmly cohesive and salt cemented; abundant diffuse salts; rock particles subangular and unstained but some ghosts strongly disaggregated; distinct boundary,
803e
55
–
70
cm
yellowish brown to strong brown (10YR 5/4 - 7.5YR 5/6) sandy gravel; very firm; ice cemented; some diffuse salts; the horizon occurs as a lens only in one side of the pit; rock particles subangular and unstained; distinct boundary,
803f
70
–
90
cm
yellowish brown (10YR 5/6) pebbly to bouldery sandy gravel; weakly cohesive; some salts scattered and around stones; rock particles subangular and unstained; indistinct boundary,
803g
90
–
100
cm
yellowish brown (10YR 5/6) pebbly to bouldery sandy gravel; weakly cohesive; some salts scattered around stones; rock particles subangular and unstained; distinct boundary,
803h
100
–
130
cm
yellowish brown (10YR 5/6) pebbly to bouldery sandy gravel; weakly cohesive; some salts scattered around stones; rock particles subangular and unstained; distinct boundary,
803i
130
–
135
cm
strong brown (7.5YR 5/6) sandy pebbly and cobbly gravel , possibly a paleosol; loose; salts diffuse and around stones; rock particles subrounded and subangular with some partly oxidised and weakly pitted