Monday, 6 October 2008
George R. Brown Convention Center, Exhibit Hall E
The increase in aridity and wind strength in periglacial regions during late Cenozoic glacials promoted the offshore transport of dust, with the flux of limiting nutrients to oceanic environments promoting plankton blooms. Glacial sediments from deep sea and neritic sediments in the mid latitude North Pacific and North Atlantic contain high concentrations of organic-walled, calcareous, and siliceous microfossils. The relatively rapid sedimentation of organic particles (pollen and embryophyte spores as well as the cysts of dinoflagellates and other algae) as well as other biogenic particles (e.g. planktonic foram tests) promoted preservation. This sequestered large volumes of carbon in the deep sea, dampening the greenhouse effect, and promoting the expansion of ice sheets. The exposure of continental shelves during glacial maxima promoted oxidation and dissolution, returning some of the carbon dioxide to the atmosphere, contributing to the rapid warming at glacial terminations.