Because of the paucity of exposed rock, the direct physical
record of Antarctic Cenozoic glacial history has become
known only recently and then largely from offshore shelf
basins through seismic surveys and drilling. The number
of holes on the continental shelf has been small and largely
confined to three areas (McMurdo Sound, Prydz Bay, and
Antarctic Peninsula), but even in McMurdo Sound, where
Oligocene and early Miocene strata are well cored, the late Cenozoic is poorly known and dated. The latest Antarctic
geological drilling program, ANDRILL, successfully cored
a 1285-m-long record of climate history spanning the last 13
m.y. from subsea-floor sediment beneath the McMurdo Ice
Shelf (MIS), using drilling systems specially developed for
operating through ice shelves. The cores provide the most
complete Antarctic record to date of ice-sheet and climate
fluctuations for this period of Earth’s history. The >60 cycles
of advance and retreat of the grounded ice margin preserved
in the AND-1B record the evolution of the Antarctic ice sheet
since a profound global cooling step in deep-sea oxygen
isotope records ~14 m.y.a. A feature of particular interest is a
~90-m-thick interval of diatomite deposited during the warm
Pliocene and representing an extended period (~200,000
years) of locally open water, high phytoplankton productivity, and retreat of the glaciers on land.
