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Revealing the history of the Arctic Ocean
Even taking into account concepts of global warming, it’s difficult to envisage a time when the climate was warm enough for dinosaurs to roam the Earth’s northern latitudes. And, although we know that dramatic climate changes have occurred in the Arctic since the dinosaur age, much of the detailed evidence of the history of the Arctic lies hidden in rocks beneath the Arctic Ocean.
Bernard Coakley, associate professor of geophysics at the University of Alaska Fairbanks, will speak at the Pac Com conference on Feb. 22 in Anchorage on the results of geological and geophysical research in the Arctic Ocean. Coakley has spent much of the past 12 years researching the geology of the various ridges, plateaus and sub-basins that lie beneath the ocean. Submarine and ice breaker Coakley led the geophysics program of SCICEX, a series of unclassified cruises to the Arctic on U.S. submarines.
And in the late summer of 2005 Coakley was co-chief in a research cruise across the Arctic Ocean by the U.S. Coast Guard icebreaker Healy. That cruise collected about 2,200 kilometers of multi-channel reflection data that reveal the stratigraphic record of the ocean — the cruise crossed all of the major ocean basins and ridges. The seismic surveys used two 250 cubic inch airguns, a 200 to 300-meter streamer and nearly 100 sonobuoy deployments. At one point a Swedish icebreaker helped with surveying in relatively heavy pack ice.
Plate boundaries
Identifying boundaries between the Earth’s tectonic plates under the Arctic Ocean will shed light on the Mesozoic history of the ocean, Coakley says. And an understanding of the Mesozoic history will particularly aid understanding of major ocean features such as the Lomonosov Ridge, the Alhpa-Mendeleev Ridge, the Makarov Basin and the Canada Basin. Knowledge of the marine geology will help elucidate the history of terrestrial features such as the Brooks Range and the North Slope of Alaska.
Deciphering the geologic history, together with data from sediment and ice cores, will enable the study of global climate changes in ancient times and permit the construction of climate models during periods of high carbon dioxide concentration.
—Alan Bailey
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