Antarctica Flashcards
Antarctica map without ice including effects of isostatic rebound. Shows EA = passive margin, WA = sea lochs
Jamieson
Work from 2013 suggesting that EAIS wasn’t stable during the pliocene, resurfacing argument from the 1990s.
Cook et al
Pliocene dates
5.5-2.5 Ma
Sirius deposits: Glacial Till w/ rounded clasts & striated lithology = WARM-BASED (LIKE ICELAND)
Mt. Sirius, Royal Society Range work in 1993
Denton
Work in 1995 to produce a geomorphological map of Dry Valleys … disprove the Sirius deposits.
Sugden et al
Arena valley…
sub-glacial meltwater deposit, overprinted by cold-based glacier erosional signature….
MWFs picked up debris which couldnt have come from periphery/slopes.
Dated at….
15Ma
Snowfall collected in wedges at the periphery of tundra polygons of airfall ash deposits dated at.
Implies stable, cold environment
8Ma and up to 15Ma
Beacon valley…
boulder clay on top of ash on top of regelation ice. Regelation ice shows warm based ice must have flowed over bed….
Ash dated at …
Erratic dated at (showing ice must have been there fore at least)
8Ma and 13-14Ma
Work in 2008 in Corrie, Olympus range…
Morraine crest marks transition from warm based to cold based glacier. Ash at separation dated at…
14Ma
Cape Robert Drilling, in 2001… by …
33 glacial cycles from …
Naish
34-17Ma
Arena valley…
COMPLETELY UNALTERED volcanic ash avalanche deposit aged,
upper pliocene morraine dated …
Shows glacier THICKENING during pliocene
11.3Ma and 3-4Ma
2 stages of cooling:
terrestrial cooling … ocean cooling …
10 degrees, 6 degrees
2 episodes
33 orbitally driven glacial/interglacial cycles w/ progressive cooling. AGE
‘AGE’ - present permanent ice sheet controlling the high polar climate. Only subject to sea-level forcing
34-17Ma and 13.6Ma
Modelled growth of ice sheet in 2014
Jamieson
Work from ‘….’
Looked at diamictites of the ‘…..’ group on the E of EAIS
Prince charles mountains.
uplifted from bsl to 1400m. Found well preserved marine diatoms giving incontrovertible ages. Seds were from’…..’ E of EAIS dynamic prior to Pliocene at least
Hambrey et al …. pagodroma … strongly fluctuating glaciers in fjords, like Greenland today.
Working on Gamburtsev mountains in 2013, found clear fluvial signature, locally overdeepened by Mountain glaciers.
Rose et al.
Fluvial signatures in Gamburtsev mountains formed w/ abundance of water in ‘….’ with a constant glacial signature subce
Miocene
Ice shelf size of wales collapsed within a month.
Name, Year
Larsen B Ice shelf, 2002
Significant thinning to WAIS shown by his work in 2012.
warm pacific waters … inland ice initially thought to be safe
Pritchard
Paper in 2014 by ‘….’ showed MTGs increased in velocity by ‘…’ between ‘…’ velocity now > ‘….’
Mouginot, >1.5km/yr, 1996-2008, >3km
Studied BLUE ICE MORRAINES in 2016.
looked at cosmogenic isotope age relationships of ‘…’ samples.
LGM @ ‘…’, ice at its max at ‘…’, most abrupt ice drop ‘…’ with SLR ‘…’
Hein et al, 2016, ‘71’, 21Ka, 15-10Ka, 6-3Ka, 2m
Looked at OLDER deposits in Ellsworth Mountains in 2017 ‘….’. High level erratics exposed for at least ‘….’, highly striated bedrock found minimum MAT req’d to explain these ‘…’ actual MAT ‘….’
Sugden, 2.5 Myr, -11, -30
18 O records showing cooling since ‘….’, T step down in ‘….’ caused shift from incomplete to complete IS. Patagonian climate in ‘…..’ according to …. ‘….’
40Ma, Mid Miocene, Mid Miocene, Jamieson
Work in 2009 by ‘….’ suggesting katabatic winds and IS in Ellsworth mountains for at least ‘….’
Showed either whole WAIS stable or just 3 regional upland areas survived warm period of pliocene
Pollard and Deconto, >2.5Ma
Work in 1981 suggesting WAIS has a ‘weak underbelly’ due to being marine based
Hughes
Work in 2005 using radar altimetry showed clear concentration of surface lowering in Amundsen sea sector. Consistent signal for ‘…’ years
Davis et al, 30
Studies by ‘..’, ‘….’, ‘….’, ‘…’ all agree that Amundsen/bellingshausen sectors are consistently losing ice
Pritchard, Davis, Wingham, Zwally
Work in 2008 showing areas of WA massively in -ve MB for last 30 yrs
Rignot
Work in 2009 by ‘…’ showing a ‘…’ thinning rate at the grounding line of the PIG
Wingham, 3m/yr
Work in 2014 by ‘…’ showing a ‘…’% increase in speed between ‘….’ at the GL of PIG
Mouginot, 42, 96-07
Work in 2013 by ‘…’ showing PIG retreat of GL up to ‘….’km since ‘decade’
Park et al, 30, 70s
Work in 2009 by ‘….’ on WAIS stability…
If acceleration continues at present rate, the main trunk will be afloat within ‘….’ years, ‘….’x faster than anticipated
Wingham, 100, 6
Work in 2006 by ‘…’ showing PIG lower basin instability can contribute ice to raise GSL by ‘….’cm
Vaughan, 24
£7million Programme from 2012-2017 by ‘….’ funded by ‘…..’ to look at PIG
iStar, NERC
Glaciers/ice draining into amundsen sea embayment contribute ‘…’% to GSLR
7
PIG WORK:
9 patches of ‘…‘x’…‘km, covering roughly ‘…’% of PIG main trunk & tributaries
10,15 , 15
PIG WORK:
Central trunk: generally flat, but one bump protruding ‘….’m into ice
300m
PIG WORK:
Eastern tributary, near GL. v.high asperity.
lineations w/ amplitude of ‘….’m
Evidence of immature landscape, still in process of being shaped by ice
500m
PIG WORK
basal traction figures, higher, where bed is rough.
main trunk of PIG generally have relatively low values
70
