Soil moisture & permafrost investigations; toposequence and landscape relationship differences; second in sequence
Description:
About 200m to the west of the northern end of the Marble Point runway and east of a small lake; a slightly hummocky low moraine ridge alongside and north of a small flat hollow; just below the crest of the ridge on the south slope and approximately 15m from site 639
Altitude:
73 m
Aspect:
S
Slope:
7 °
Location Data
Observer
IBC
GGC
GPS
Yes
Latitude Longitude DMS
77° 24.77' S 163° 39.78' E
77° 24.7' S 163° 40.0' E
Latitude Longitude DD
-77.41280 163.66300
-77.4117 163.667
Latitude longitude precision DD
0.00008 0.00008
0.0008 0.008
Locality
Marble Point, western McMurdo Sound
Survey
USGS Antarctica Topographic Series 1:50,000; Marble Point, Antarctica
Climate
Soil climate zone:
Coastal Antarctic
Site temperature profile
Depth (cm)
Soil temp (°C)
Notes
10
0
179
-10.1
Estimated mean annual temperature:
-18
°C
Frozen ground depth:
50 cm
Frozen type:
Hard ice-cemented
Frozen comment:
50cm
Geology
Geological setting:
The surface is undulating with deposits of till; the region is an old landscape of granite and granodiorite, gneiss and marble rocks; there are some old weathering and phillipsite deposits in the region; the till has probably come from the Wilson Piedmont Glacier and includes granodiorite, gneiss, marble and some dolerite; the till is silty in places and this may have resulted from postglacial fluvial activity
Patterned ground:
Nets 15-20m across with active cracks 20cm deep
Surface weathering or surface features:
Non pavementic with predominantly small boulders and cobbles and subangular to angular; distinct oxidation and staining on some clasts may in part be pre-weathering
Soil
Soil parent material:
Sandy to silty granitic and granodioritic stony till
Previous disturbance:
Extensive construction, earthmoving and human activity in the late 1950's in the general area; some nearby bulldozer tracks
Patchy snow on adjacent side slopes; soil surface is dry
Biological activity:
Some yellow lichen in patterned ground cracks; also some black dried cyanobacterial matter; some nearby moss patches
Profile Description
Horizon
Depth
Description
640a
-3 – 0 cm
surface cobbly to granular gravel; rock particles subrounded to subangular, some with light staining; a few green algal masses; some carbonate coatings,
640b
0 – 5 cm
olive (5Y 5/3) gravelly sand; loose; rock particles subangular, some with weak staining; some distinct carbonate coatings; distinct boundary,
640c
5 – 22 cm
light yellowish brown (2.5Y 6/4) sandy gravel; loose; rock particles subangular, some weakly stained; some distinct carbonate coatings; distinct boundary,
640d
22 – 30 cm
light yellowish brown (2.5Y 6/4) sandy gravel; weakly to moderately cohesive; rock particles subangular, some weakly stained and partly altered (relict); some distinct carbonate coatings; sharp boundary,
640e
30 – 45 cm
light yellowish brown (2.5Y 6/4) sandy to silty gravel; firm to very firm rock particles subangular; weakly developed vesicular structure; indistinct boundary,
640f
45 – 50 cm
pale olive (5Y 6/3) sandy to silty gravel; very firm; moderately developed vesicular structure; rock particles subangular; sharp boundary,
640g
50 – 66 cm
drill core; light grey (5Y 7/2) sandy to silty gravel,
640h
66 – 82 cm
drill core; light grey (5Y 7/2) sandy to silty gravel,
640i
82 – 91 cm
drill core; light grey (5Y 7/1) sandy to silty gravel,
640j
91 – 95 cm
drill core; light grey (5Y 7/2) sandy to silty gravel,
640k
95 – 120 cm
drill core; pale olive (5Y 6/3) sandy to silty gravel,
640l
120 – 138 cm
drill core; light grey (5Y 7/1) sandy to silty gravel,