Impressive work on the Law glacier by Bader et al. indicating long term stability at least on that side of the polar plateau. The optimistic headline in the phys.org article overstates the case. An error in the article is publication date, which was apparently in February.
https://phys.org/news/2017-08-validates-east-antarctic-ice-sheet.htmldoi:10.1016/j.quascirev.2016.12.005
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Abstract: Till in an extensive blue ice moraine in the central Transantarctic Mountains at Mt. Achernar shows
relatively continuous deposition by East Antarctic derived ice throughout the last glacial cycle. The most
recently exposed material along the active margin of the Law Glacier (Zone 1) has hummocky topog-
raphy that transitions into to a relatively flat region (Zone 2), followed by a series of ~2 m high
continuous, parallel/sub-parallel ridges and troughs (Zones 3e5). The entire moraine is ice-cored. Past
surface changes of <40 m are indicated by a lateral moraine at the base of Mt. Achernar and substantial
topographic relief across Zone 3.
Pebble lithology and detrital zircon geochronology were analyzed on samples along a 6.5 km transect
across the moraine which formed from sub- and englacial debris. Beacon and Ferrar Supergroup rocks
comprise most rock types on the moraine surface. Overall, pebbles in Zones 1, 4 and 5 are dominated by
igneous rocks of the Ferrar dolerite, whereas Zones 2 and 3 have ~40% more Beacon Supergroup sedi-
mentary rocks. Zone 4 is characterized by distinctly colored lithologic bands, 5e20 m wide, that alternate
between dominant Beacon and Ferrar rock types. When combined with surface exposure ages, we
conclude that Zones 2 and 3 contain sediment accumulated through the last glacial maximum (LGM). In
contrast to pebble data, the U-Pb zircon data from till across all zones show little variability and are
consistent with a Beacon Supergroup source, as samples show significant populations from the Prote-
rozoic, ~550-600 Ma and ~950-1270 Ma, as well as the late Archean ~2700-2770 Ma. The Mackellar,
Fairchild, and lower Buckley Formations are interpreted as dominant sources of the detrital zircons. The
zircon data lack the spatio-temporal variability indicated by the pebble fraction because the local Ferrar dolerite is not zircon bearing, highlighting the broader importance of using multiple techniques when interpreting provenance changes over time.
Rather than reflecting major changes in ice flow path over time, the provenance changes are inter-
preted to indicate relative stability of the East Antarctic ice sheet, as the Law Glacier tapped into and
eroded successively lower stratigraphic units of the Beacon Supergroup. This has important implications
for interpreting offshore provenance records.
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Very nice. Unfortunately paywalled. I attach figs 3b,c and part of 9 to give a flavor. They conclude:
" ... that is, provenance changes can be explained solely by Law Glacier tapping into successively lower stratigraphic units of the Beacon Supergroup, rather than indicating significant changes within East Antarctic ice sheet catchment boundaries. This has important implications for interpreting long temporal record from cores, such as ANDRILL. For instance, provenance analysis of a core collected downstream of an outlet glacier, such as the Law/Lennox-King Glacier system ... "
sidd