A few years ago the only information available on the deep Arctic Ocean sediments and history was based on a few short cores taken incidentally from floating ice islands by Americans and Russians. Summer work in the Beaufort, Chukchi, Laptev, Kara, and Barents Seas provided additional information but only for the marginal parts of the Arctic Ocean. Beginning in 1963, a systematic coring program was initiated from ice-island T-3 by Lachenbruch and Marshall of the U.S. Geological Survey. To date, 550 cores have been taken along the drift course of T-3, covering almost 1 million sq km of the central Arctic Ocean. Such coverage of an ocean from an iceberg is unique.

Because these cores represent the only record for such a large part of this important ocean, study has been designed to yield maximum data concerning mineralogy, petrology, paleontology, sedimentary structures, glacial erratics, paleomagnetism, and heat flow. Paleomagnetism has provided a stratigraphic framework for all of the studies. The objective of a paleoecologic interpretation of the Arctic Ocean has led to a variety of data, including information on the permanence of the ice pack and identification of the oldest sediment (Cretaceous) known in the central Arctic Ocean. Also, studies on paleomagnetism, sediments, silicoflagellates, and Foraminifera have combined in a unique manner to help establish a time reference for plate tectonics of the Arctic Ocean.

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