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Department of Geography

Staff Profile

Publication details for Dr Eleanor Maddison

Leventer, A., Domack, E., Dunbar, R., Pike, J., Stickley, C., Maddison, E., Brachfeld, S., Manley, P., & McClennen, C., East Antarctic Margin marine sediment record of deglaciation. GSA Today. 2006;16:4-10.

Author(s) from Durham

Abstract

The Antarctic shelf is traversed by large-scale troughs developed
by glacial erosion. Swath bathymetric, lithologic, and
chronologic data from jumbo piston cores from four sites along
the East Antarctic margin (Iceberg Alley, the Nielsen Basin, the
Svenner Channel, and the Mertz-Ninnis Trough) are used to
demonstrate that these cross-shelf features controlled development
of calving bay reentrants in the Antarctic ice sheet during
deglaciation. At all sites except the Mertz-Ninnis Trough, the
transition between the Last Glacial Maximum and the Holocene
is characterized by varved couplets deposited during a
short interval of extremely high primary productivity in a fjordlike
setting. Nearly monospecific layers of the diatom Chaetoceros
alternate with slightly more terrigenous layers containing
a mixed diatom assemblage. We propose that springtime
diatom blooms dominated by Chaetoceros were generated
within well-stratified and restricted surface waters of calving
bays that were influenced by the input of iron-rich meltwater.
Intervening post-bloom summer-fall laminae were formed
through the downward flux of terrigenous material sourced
from melting glacial ice combined with mixed diatom assemblages.
Radiocarbon-based chronologies that constrain the timing
of deposition of the varved sediments within calving bay
reentrants along the East Antarctic margin place deglaciation
between ca. 10,500–11,500 cal yr B.P., post-dating Meltwater
Pulse 1A (14,200 cal yr B.P.) and indicating that retreat of ice
from the East Antarctic margin was not the major contributor to
this pulse of meltwater.