Abstract:
In 1985, with the initiation of JOIDES Resolution and the second phase of scientific drilling, scientists gained the capacity to drill in some of the more remote and inhospitable reaches of the world oceans, including the polar oceans. One immediate regional target was the southern ocean, where nearly 10 km of sediment were recovered at more than 25 sites during 4 legs of drilling. As a result of antarctic drilling it became evident that ice sheets were present on Antarctica as long ago as the earliest Oligocene. Thick sequences of glacially deposited debris found in Prydz Bay, together with similar deposits found earlier in McMurdo Sound on the opposite side of the continent, indicated widespread glacial activity not atypical of continental ice sheets. Some of the oldest glacial sediments, however, were deposited in the late Eocene, suggesting that the very first ice sheets, albeit small, formed nearly 40 mya. Thus, it appears that glacial activity was limited regionally to portions of East Antarctica until about the earliest Oligocene (about 35 mya).