Battye Glacier Formation Paleontology and Sedimentology, Beaver Lake Region, Antarctica

Glacimarine strata of the Battye Glacier Formation (c.130 m thick),
Pagodroma Group, exposed in the Amery Oasis of East Antarctica,
provide a record of late Miocene palaeoenvironmental conditions in an
ice-distal setting. The formation overlies the Amery Erosion Surface
(c.300 m to c.270 m above sea level) that formed during an advance of
the Lambert Glacier, at least 750 km further north than today, into
Prydz Bay (ODP Site 739). Two lithological members: a grey and muddier
Lower Member and a brown, sand-rich Upper Member, reflect variation in
proximity to the terminus of the Lambert Glacier. Ice-distal,
glacimarine, diatom-bearing mud (up to 12% biogenic silica) and in
situ articulated molluscs occur in the Lower Member. Similar Neogene
strata are known on land only from the Pliocene Sorsdal Formation in
the Vestfold Hills, near the Antarctic coast. The Battye Glacier
Formation is significant because of its inland location, which
indicates that ice-distal marine conditions existed 250 km inland from
the current Amery Ice Shelf edge. Three stratigraphic intervals of
diatom-bearing mud are recognized from glacially reworked clasts and
from in situ strata informally referred to as the McLeod Beds and
Bed A.

The diatom-bearing mud also contains sponge spicules and minor
silicoflagellates and ebridians. Marine diatom biostratigraphy
constrains the age of the beds to between 10.7 and 9.0 Ma (late
Miocene). Abundant benthic diatoms suggest deposition within shallow
euphotic depths. The high abundance of intercalary valves of Eucampia
antarctica from an interval of the McLeod Beds suggests that there was
less winter sea-ice than in Prydz Bay today. It is unlikely that
sea-ice was perennial because the presence of Thalassionema spp. and
Stellarima stellaris (Roper) Hasle et Sims suggests that summer
sea-surface temperatures were too warm (> 0 degrees C and > 3 degrees
C respectively). The palaeoclimate at the time of deposition appears
to have been analogous to that in modern fjords of East Greenland
(e.g. Kangerdlugssuaq Fjord), which is consistent with the
depositional model proposed previously for the Pagodroma Group. The
three diatom-bearing mud intervals were deposited in the Amery Oasis,
c.250 km inland of the current Amery Ice Shelf edge, when the East
Antarctic Ice Sheet was reduced in size relative to today.

Further information can be found in reference:

Whitehead, J.M., Harwood, D.M. and McMinn, A., 2003. Ice-distal upper
Miocene marine strata from inland Antarctica. Sedimentology v. 50,
22pp.