Deglaciation chronology, sea-level changes and environmental changes from Holocene lake sediments of Germania Havn Sø, Sabine Ø, northeast Greenland

Abstract

AbstractGermania Havn Sø is located at the outermost coast of northeastern Greenland. According to radiocarbon dating, the lake basin was deglaciated in the early Holocene, around 11,000 cal yr BP. At that time the lake was a marine bay, but the lake was isolated soon after deglaciation at ~ 10,600 cal yr BP. The marine fauna was species-poor, indicating harsh conditions with a high sedimentation rate and lowered salinity due to glacial meltwater supply. The pioneer vegetation around the lake was dominated by mosses and herbs. Deposition of relatively coarse sediments during the early Holocene indicates erosion of the newly deglaciated terrain. Remains of the first woody plant (Salix herbacea)appear at 7600 cal yr BP and remains of other woody plants (Salix arctica,Dryas octopetala,Cassiope tetragonaandEmpetrum nigrum) appear around one millennium later. Declining concentrations ofD. octopetalaand the caddis flyApatania zonellain the late Holocene probably imply falling summer temperatures. Only moderate changes in the granulometric and geochemical record during the Holocene indicate relatively stable environmental settings in the lake, which can probably be explained by its location at the outer coast and the buffering effect of the neighboring ocean.