Air temperature trends across the North Atlantic region in the early icehouse world
Abstract
One of the most characteristic features of the modern icehouse climate in the North Atlantic region is a pronounced air temperature gradient between Northwestern Europe and Greenland. This east-west temperature gradient results from a strong meridional oceanic circulation pattern: the North Atlantic Drift transports warm and saline surface waters from the low latitudes towards the Arctic region, along the coast of Northwestern Europe. In the Arctic, cold and fresh water sinks and flows southwards along the east Greenland margin (North Atlantic Deep Water).
The precise timing of the development of these oceanic patterns is still uncertain due to inconclusive existing data. To better understand climate change over the North Atlantic region during the Earth's early icehouse phase, we present mean annual air temperatures (MAAT) derived from branched glycerol dialkyl glycerol tetraethers from locations around the northern Atlantic Ocean. Our record spans Upper Eocene-Lower Miocene successions ( 35 to 28Ma) from marine sites in Denmark and the Labrador Sea (ODP Site 647A) and Newfoundland drift deposits (IODP Expedition 342 Sites U1411 and U1406). A comparison between MAAT records in these locations and the published MAAT record from the Greenland Sea (ODP Site 913) makes it possible for the first time to deconvolve high and low latitude air temperature signals in the region. Furthermore, our record suggests the presence of a ca.4°C MAAT gradient across the eastern and western flanks of the mid latitude North Atlantic during the middle Oligocene.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMPP13E1362S
- Keywords:
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- 9325 Atlantic Ocean;
- GEOGRAPHIC LOCATIONDE: 1635 Oceans;
- GLOBAL CHANGEDE: 4899 General or miscellaneous;
- OCEANOGRAPHY: BIOLOGICAL AND CHEMICALDE: 4999 General or miscellaneous;
- PALEOCEANOGRAPHY