Le Geotop - Dr. Stijn De Schepper : Pliocene Nordic Seas... (30-01-2017)

Dr. Stijn De Schepper : Pliocene Nordic Seas... (30-01-2017)

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Dr. Stijn De Schepper (Uni Research Climate and Bjerknes Centre for Climate Research)

Pliocene Nordic Seas paleoceanography: surface circulation and sea ice evolution

Lundi 30 janvier 2017 à 11h00/ Monday, January 30, 2017, 11:00am

Local PK- R250, 201 ave. Président-Kennedy, UQAM

Résumé / Abstract:

The Nordic Seas link the North Atlantic and Arctic Ocean, and play an important role in the global overturning circulation and heat transport into the Arctic. This region underwent fundamental changes during the Pliocene, a time period when global climate was generally 2–3˚C warmer than today. Understanding the Pliocene Nordic Seas paleoceanography can thus shed light on how ocean circulation, northward heat transport and regional climate respond to globally warmer conditions. In this challenging region, poor preservation of calcareous microfossils has meant that traditional proxies (e.g. foraminifer stable isotopes) are of limited use for marine isotope stratigraphy and paleoceanography. There are however other proxies that prove instrumental for establishing detailed chronologies, reconstructing surface ocean circulation and sea ice extent. I will discuss marine palynological and geochemical records from the Norwegian and Iceland Seas to illustrate their importance for (1) establishing a Pliocene stratigraphic framework for the Nordic Seas, (2) documenting the development of a modern Nordic Seas surface circulation during the Early Pliocene and (3) reconstructing for the first time the seasonal sea ice extent in the Late Pliocene Iceland Sea.