Ross Sea Region Soil Sites
918000
918
15-Dec-1999
IBC
Beacon Valley upper Taylor Glacier McMurdo Dry Valley region, Transantarctic Mountains; about mid valley
Soil examination of a potential LTER site in Beacon Valley
Ross Island and Vicinity 1:250 000; US Geological Survey 1986
CS Pro & Lscp
No
160.6120
-77.8325
77deg 50.0'S
-160deg -36.7'E
cf. Notes for DESCR below
0
Nil
1,000
cf. Notes for GEOLAND below
Xerous to subxerous; a dry site with no adjacent snow patches
-28
Inland mountain
Sandy till from predominantly dolerite (70%) and sandstone, with dolerite boulders appearing to occur mainly on the surface and covering 20-30% of the surface
Nil observed
Nil
SURFACE WEATHERING or |
SURFACE FEATURES |
cf. Notes for SURFWEA below
Nil
918a 1-0cm
101
surface cobbles
102
pebbles and granules forming a weakly pavementic surface
103
clasts subangular to rounded, some stained but some exfoliated
104
salts beneath some clasts
105
sharp boundary,
918b 0-2cm
201
yellowish brown (10YR 5/4) pebbly granular sand
202
moderately cohesive
203
moderately developed vesicular structure
204
diffuse white salt flecks around stones
205
rock particles (dolerites) moderately stained but many internally altered to brown to strong brown (7.5YR 5/4 |
-5/6) oxidations |
206
larger clasts mainly subrounded but smaller particles mainly rounded to subrounded
207
diffuse boundary,
918c 2-5cm
301
yellowish brown (10YR 5/4) pebbly granular sandy
302
weakly cohesive
303
discontinuous salt patches
304
rock particles mainly subangular and stained and many altered
305
diffuse boundary,
918d 5-15cm
401
very pale brown (10YR 5/4) granular pebbly sand with some cobbles
402
weakly to moderately cohesive
403
salts diffused through the horizon larger rock particles mainly angular sandstone and unstained
404
diffuse boundary,
918e 15-25cm
501
yellowish brown (10YR 5/4) granular pebbly silty sand with occasional larger clasts
502
loose
503
rock particles mainly subangular, weakly to moderately stained and partly altered
504
diffuse boundary,
918f 25-40cm
601
yellowish brown (10YR 5/4) granular pebbly silty sand with occasional larger clasts
602
loose
603
a few fine salt flecks
604
rock particles mainly subangular with smaller particles subrounded and partly altered
605
diffuse boundary, on yellowish brown gravelly sand
Yes
Dry frozen
0
3
(N/Fnd)
Descr
A bouldery surface, nearly all dolerite with some up to 2m but most >75cm; part of a gently northwards sloping, broad till plain valley floor; the surface is |
intermediate in age with younger till surfaces closer to the Taylor Glacier and older till surfaces at higher levels on the valley side; the ground surface is uneven |
with slight bouldery hummocks or rises separated by small flattish smoother patches; accumulations of pebble and granules in the lea of some boulders |
Geoland
Beacon Valley is a very old valley with Miocene aged tills at higher levels in the valley; close to the glacier there is a series of well marked younger recessional |
moraines with granitic erratics indicative of earlier ice advances up valley from Taylor Glacier; granite erratics also occur in the old tills at higher elevations; the |
locally outcropping rocks are Beacon Sandstone and Ferrar Dolerite; these are present in the till which appears to be locally derived at this site as there is no sign |
of any erratics |
Surfwea
Dolerite clasts strongly stained; some pitting on fine grained dolerite and moderate exfoliation on coarse grained dolerite; moderate to weak ventiforms; some |
polish on sheltered rock faces; moderate rounding from surface exfoliation; a few salt patches under some clasts |
Soluble Salt |
Concentration |
91800001
918a
1-0cm
-1
0
1.82
46.00
0.33
none
91800002
918b
0-2cm
0
2
1.29
95.00
1.93
none
91800003
918g>2mm
0-5cm
0
5
0.37
>2mm
91800003
918h<2mm
0-5cm
0
5
0.53
<2mm
91800004
918c
2-5cm
2
5
1.32
90.00
3.80
none
91800005
918d
5-15cm
5
15
1.38
88.00
1.66
none
91800005
918i>2mm
5-15cm
5
15
1.19
>2mm
91800005
918j<2mm
5-15cm
5
15
1.71
<2mm
91800006
918e
15-25cm
15
25
1.52
92.00
1.12
none
91800007
918k>2mm
15-30cm
15
30
0.85
>2mm
91800007
918l<2mm
15-30cm
15
30
1.61
<2mm
91800008
918f
25-40cm
25
40
1.50
94.00
1.02
none
12-Dec-2005
Page 893 of 896
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