The
continental rise around the Antarctic margin is commonly occupied by
large sediment ridges or mounds that result from the interaction between
down-slope gravitational processes and bottom contour-currents. Geophysical
and geological research on the Antarctic continental rise ridges, have
greatly increased our understanding of deep-water sedimentary processes
in glaciated margins including general relationships between proximal
and distal sedimentation. Sediment supply to the Antarctic shelf, slope
and rise is highly cyclic. Episodes of ice advance result in erosional
surfaces on the continental shelf, overcompacted sediment and steeply
prograded wedges on the outer shelf troughs and on the upper slope.
Unconsolidated and unsorted material supplied by ice streams causes
slope instability and the generation of slumps and turbidity flows that,
in the continental rise develop channel-levee complexes characteristic
of deep-sea fans. The finer-grain component of the turbidity currents
can be entrained by ambien bottom contour-currents and deposited in
sediment ridges.
Interpreting the sedimentary record from the continental
rise deposits in terms of advances and retreats of the ice sheet (tubidite
record) versus changes in paleoceanographic regime (contourite record)
and to estimate which of these processes is most important in any
particular time, has proven challenging. Sediments within these ridges
are studied in the context of the PROSEDANT project to obtain the
distal record (warmer vs. cooler) of glacial advances and retreats
of the East Antarctic Ice Sheet. To interpret this record we will
need first to learn to separate the paleoceanographic record provided
by the bottom contour-current deposits and the record of advances
and retreats of the ice sheet provided by the down-slope deposits.
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