Ross Sea Region Soil Sites

Taylor Dry Valley, McMurdo Dry Valley region near Lake Bonney

Soil sequence weathering examination

USGS 1:50,000 Antarctic Topo. Ser. Lake Bonney Quadrangle

cf. Notes for DESCR below

cf. Notes for GEOLAND below

The site is dry with no snow drift or glacier runoff

SOIL MOISTURE STATUS

Bouldery granitic till

SOIL PARENT MATERIAL

SURFACE WEATHERING or

SURFACE FEATURES

Surface boulders medium with few upstanding; strong cavernous weathering and distinct surface staining; moraine loop surface with a subdued form

PREVIOUS DISTURBANCE

surface boulders and cobbly granular sand

rock particles weakly stained with some cavernously weathering,

olive brown to light yellowish brown (2.5Y 5/4 - 10YR 6/4) granular bouldery gravel

scattered small salt precipitations on rock edges

rock particles angular to subrounded and weakly stained

indistinct boundary, on olive brown (2.5Y 5/4) sandy gravel

FROZEN GROUND DEPTH(cm)

SOIL WEATHERING STAGE

On the SE side of Lake Bonney, immediately adjacent to and near the snout of the Hughes Glacier; a bouldery surface which forms part of a series (4th) of

moraine loops marking glacial stages; the site is on the ridge of the 4th moraine loop which is marked by a ridge of boulders approximately 65m from the glacier

edge

Alpine glaciers show clear geomorphic evidence of former advance and retreat stages with a series of small closely spaced ridges or terminal moraines over

about 100m indicating the former glacier position; weathering increases with distance away from the glacier, suggesting that there may be a considerable age

difference between the moraine surfaces; this 4th surface on the shallow ridge crest of the moraine loop and is clearly more weathered than the surfaces nearer to

the glacier

Vol. Moisture

Drill Vol

Vol. Moisture

(BD=2)

Soluble Salt

Concentration

Gravimetric

Moisture

Part. Size

0.02-0.002

Part. Size

0.05-0.02