Postglacial environmental succession of Nettilling Lake (Baffin Island, Canadian Arctic) inferred from biogeochemical and microfossil proxies

摘要

Nettilling Lake (Baffin Island, Nunavut) is currently the largest lake in the Canadian Arctic Archipelago.udDespite its enormous size, this freshwater system remains little studied until the present-day. Existingudrecords from southern Baffin Island indicate that in the early postglacial period, the region was submergedudby the postglacial Tyrell Sea due to isostatic depression previously exerted by the Laurentide IceudSheet. However, these records are temporally and spatially discontinuous, relying on qualitativeudextrapolation. This paper presents the first quantitative reconstruction of the postglacial environmentaludsuccession of the Nettilling Lake basin based on a 8300 yr-long high resolution sedimentary record. Ourudmulti-proxy investigation of the glacio-isostatic uplift and subsequent changes in paleosalinity andudsediment sources is based on analyses of sediment fabric, elemental geochemistry (m-XRF), diatomudassemblage composition, as well as on the first diatom-based oxygen isotope record from the easternudCanadian Arctic. Results indicate that the Nettilling Lake basin experienced a relatively rapid and uniformudmarine invasion in the early Holocene, followed by progressive freshening until about 6000 yr BP whenudlimnological conditions similar to those of today were established. Our findings present evidence foruddeglacial processes in the Foxe Basin that were initiated at least 400yrs earlier than previously thought.