Paleoceanographic changes along the western Spitsbergen margin, evidence from planktic microfossil during the last 10 kyr BP

Abstract

Marine microfossils record oceanographic changes that are closely linked to climate variability. We use diatoms, planktic foraminifera, and calcareous nannofossils to reconstruct the paleoceanographic evolution along the western margin of Spitsbergen (Arctic) during the last 10 kyr BP. The data are compared with other records from the western margin of Spitsbergen. We recognize three distinct units corresponding to the late phase of the early Holocene, the middle Holocene, and the late Holocene.

The results indicate warm sea surface conditions along the western margin of Spitsbergen from 10 to 7.5 kyr BP, simultaneous to a maximum of summer insolation. Maximum advection of North Atlantic Water (NAW) occurs between 10 and 9 kyr BP, corresponding to the last part of the Holocene Thermal Maximum (HTM).

The microfossil association evidenced a gradual cooling of the surface water between 7.4 and 3.8 kyr BP. Surface cooling can be explained by increased water mass exchange with the Arctic Ocean and/or reduced solar insolation. From 3.8 kyr BP, we have evidence of strong seasonality, stratified surface waters, and a slight inflow of NAW. The last 2000 years are characterized by an alternation of warm and cold periods associated with a change in NAW inflow.