Soil examination of a potential LTER site in Arena Valley
Description:
The southern end of Arena Valley, about half way between Taylor Glacier and Alter Mountain, on low hummocky moraine near the foot of a short low snow covered slope; the site area is gently undulating with scattered fragmented large (1-2m) dolerite boulders; the surface has a patchy appearance with variable amounts pale sandstone or dark dolerite at the surface
Altitude:
1575 m
Aspect:
Nil
Slope:
0 °
Location Data
Observer
IBC
GPS
Yes
Latitude Longitude DMS
77° 51.55' S 160° 59.70' E
Latitude Longitude DD
-77.8592 160.9950
Latitude longitude precision DD
0.0004 0.0008
Locality
Arena Valley, upper Taylor Glacier McMurdo Dry Valley region, Transantarctic Mountains;
Survey
Ross Island and Vicinity 1:250 000; US Geological Survey 1986
Climate
Soil climate zone:
Inland mountain
Estimated mean annual temperature:
-28
°C
Frozen ground depth:
0 cm
Frozen type:
Dry frozen
Frozen comment:
Geology
Geological setting:
Arena Valley is a very old valley with Miocene aged tills on the valley floor; the tills generally become younger to the north having been derived through advances from Taylor Valley; the local rocks are Beacon Sandstone and Ferrar Dolerite; these are present in the till which appears to be locally derived as there is no sign of any erratics
Patterned ground:
Nil
Surface weathering or surface features:
A cobble boulder pavement with some upstanding (75cm) fragmented dolerite; strong staining on dolerite with some pitting and exfoliation on corse grained clasts; strongly developed ventiforms; well developed polish and some rounding due to abrasion; thick salt accumulations beneath many surface clasts
Soil
Soil parent material:
bouldery sandy till from dolerite and sandstone with the fine fraction mainly derived from sandstone
subxerous; a dry site with no adjacent snow patches
Biological activity:
Nil observed
Profile Description
Horizon
Depth
Description
917a
-3 – 0 cm
surface cobbles; pebbles and small boulder pavement; clasts predominantly subangular and ventiform with well developed staining and polish on unabraided surfaces; salts beneath many surface clasts; sharp boundary,
917b
0 – 2 cm
larger particles mainly subangular to subrounded but smaller particles mainly rounded to subrounded; irregular boundary,; very pale brown to light yellowish brown (10YR 7/4 - 6/4) pebbly granular sand; moderately cohesive and partly salt cemented; many salt precipitations around larger clasts; dolerite particles stained and many altered with yellowish red colours
917c
2 – 6 cm
very pale brown (10YR 8/3) granular sandy silt; firmly cohesive and salt cemented; salts forming distinct white aggregates; rock particles mainly subrounded and some stained and altered; diffuse boundary,
917d
6 – 15 cm
very pale brown (10YR 8/3) granular silty sand with some cobbles; weakly to moderately cohesive; larger rock particles mainly angular sandstone and unstained; diffuse boundary,
917e
15 – 35 cm
very pale brown (10YR 8/3) cobbly silty sand; weakly cohesive; a few salts around some clasts; rock particles mainly subangular and unstained; diffuse boundary, on loose very pale brown gravelly silty sand