T184 Global Climate Changes: Abrupt Late Pleistocene Climatic Reversals and Modern Global Warming

Tuesday, 4 November 2003
1:30 PM - 5:30 PM

HOLOCENE GEOLOGIC, OCEANOGRAPHIC AND CLIMATIC HISTORY INTERPRETED FROM LAMINATED SEDIMENTS AND MODERN OCEANOGRAPHY IN FJORDS ALONG THE PACIFIC COAST OF CANADA

Paper number: T184-10
Program: Technical Sessions
Time: 3:45 PM – 4:00 PM

Authors

Abstract

Holocene age sediments found in topographically restricted fjords along the Pacific coast of Canada contain natural archives of oceanic and atmospheric conditions, and may also record paleoseismic events and changes in sea level. Annually deposited, finely laminated sediments laid down in these inlets, which have little or no bottom water oxygen content, are preserved free of bioturbation. Marine sediments recovered from our on-going work in Effingham Inlet in the adjacent Coastal Upwelling Domain, and more recently from the Seymour -Belize Inlet complex in the Coastal Transition Domain of the northwestern Pacific, contain a high-resolution record of local and regional climate change, paleoceanography, paleoproductivity and sea level change over the entire Holocene. This work involves the continued collection of sediment cores, deployment of sediment traps and moored oceanographic sensors as well as the collection of high resolution seismic and other oceanic telemetry.

In order to constrain the Holocene geologic history of this area, it is necessary to distinguish paleoceanograpic signals from overprinting episodes of rapid postglacial sea level change and sediment disturbance associated with seismic events. To accomplish this, we have combined our seven year continuous instrument record of modern coastal ocean dynamics and climate with a high-resolution analysis of modern depositional processes, to develop proxy measurements of past climate conditions recorded in the sediment record, and distinguish these from paleo-sea level and paleoseismic events. We are also developing methods of statistical time-series analyses of physical sediment properties throughout the entire Holocene to give an objective quantitative approach for detecting cyclicity in our data. Study results indicate that seismic events can be interpreted from the sediment record, sea level in the area appears to be falling from a higher sea level stand and the regional climate has oscillated on a variety of time scales throughout the Holocene. At times, climatic change has been highly abrupt.