Early Holocene cooling events in Malangenfjord and the adjoining shelf, north-east Norwegian Sea

Abstract

A high resolution study of early Holocene climate and palaeoceanography has been performed on two combined sediment cores from Malangenfjord, northern Norway. The fjord provides a regional oceanographic climatic signal reflecting changes in the North Atlantic heat flux at this latitude because of its deep sill and the relatively narrow adjoining continental shelf. Fauna and stable oxygen and carbon isotopes indicate cool, meltwater-depleted water masses in the fjord from 12000 to 11400 cal. yr BP followed by a warming between 11400-10300 cal. yr BP. The climatic variability can be explained partly by freshwater forcing hampering the North Atlantic heat conveyor, and partly by changing solar irradiance. A major cooling event at 11500-11400 cal. yr BP, followed by a rapid warming, is correlated to the Preboreal Oscillation, a widespread signal in the North Atlantic region which is probably linked to the increased meltwater flux to the northern North Atlantic at this time. Brief and small-scale cooling events between 10 300 and 10100 cal. yr BP, correlated to the onset of increased 10Be flux in the Greenland ice cores, suggest a response to solar forcing.