Ross Sea Region Soil Sites
315000
315
20-Nov-1972
IBC, GGC
Taylor Dry Valley, McMurdo Dry Valley region near Lake Bonney
Soil weathering examination
USGS 1:50,000 Antarctic Topo. Ser. Lake Bonney Quadrangle
CS+B&W Pro & Lsc
No
162.5230
-77.7167
77deg 43.0'S
-162deg -31.4'E
cf. Notes for DESCR below
20
W
350
cf. Notes for GEOLAND below
(20o)
A dry site with no snow nearby snow patches
-23
Central Mountain
Disaggregated in situ granitic bedrock
Nil observed
Nil
SURFACE WEATHERING or |
SURFACE FEATURES |
Surface boulders show moderate cavernous weathering with some accompanying bedrock wind-scoop excavation; bedrock is mainly unweathered but in a |
few places is disaggregated to 36cm depth; smaller surface clasts are mainly harder dolerite pebbles |
Nil
315 1-0cm
101
patchy cover of dolerite pebbles and granite granules
102
angular to subrounded and moderately stained,
315a 0-5cm
201
olive brown (2.5Y 4/4) granular gravel
202
loose
203
rock particles angular to subangular and weakly to moderately stained, indistinct boundary,
315b 5-10cm
301
olive brown (2.5Y 4/4) granular gravel
302
bedrock rock fabric moderately disaggregated
303
rock particles angular and weakly to moderately stained
304
a few particles moderately altered
305
indistinct boundary,
315c 15-20cm
401
olive brown (2.5Y 4/4) granular gravel
402
bedrock fabric weakly to moderately disaggregated
403
rock particles angular and weakly stained
404
indistinct boundary, on firm but disaggregating granite bedrock
Yes
a,b,c
Dry frozen bedrock
36
3
(>36cm)
Descr
On the SE side of Lake Bonney, approximately 1.3km S of the NE end of the lake, on a bench surface which is devoid of a till cover; the surface is an undulating |
bedrock surface with scattered large erratics; the site is 2m from soil 314 and appears to be a little less weathered |
Geoland
The granite bedrock surface, cut by occasional dolerite dykes, is undulating with minor till remnants but numerous large (up to 5m) granite erratics; the surface |
has probably been exposed after retreat of the local alpine glaciers which appear to have carried little debris; the surface is old judged by the cavernously |
weathered erratics and also bedrock weathering and disaggregation in places |
Soluble Salt |
Concentration |
31500001
32.00
53.40
20.70
15.50
3.10
2.60
2.60
1.10
0.92
31500002
27.00
43.60
20.70
15.70
2.00
8.00
3.60
2.10
1.13
31500003
38.00
47.20
20.20
17.00
4.10
5.10
3.80
1.40
1.04
31500001
7.00
3.30
5.70
2.40
7.80
0.80
14.80
1.90
0.30
31500002
7.20
4.60
8.70
2.20
12.40
0.90
21.40
1.60
0.30
31500003
7.10
3.00
7.20
1.20
7.00
0.70
13.60
1.00
0.10
31500001
55
15
15
15
31500002
15
85
31500003
15
85
12-Dec-2005
Page 272 of 896
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