Late quaternary glacial histories and Holocene paleoenvironmental records from northeast and southwest Ellesmere Island, Nunavut, Canada

Ice-free areas beyond the limits of the last glaciation have been proposed for much of Ellesmere Island. This hypothesis is addressed by reconstructing the late Quaternary glacial history of Lake Hazen Basin and eastern Hazen Plateau, and by coring extant lake basins beyond proposed ice margins. Diatom records from these lakes, and stable isotope records from emergent basins on Hoved Island, southwest Ellesmere Island, were used to assess Holocene environmental changes in the High Arctic.; Lateral meltwater channels, moraines and other geomorphic evidence indicate that a large trunk glacier emanating from the Grant Land Mountains coalesced with Agassiz and Greenland ice, inundating Hazen Plateau. The configuration of deglacial margins related to the trunk glacier, Holocene ice-contact deltas in Robeson Channel, and cosmogenic 36Cl dating of erratics, indicate that this occurred during the last glaciation. Thus, ice-free regions did not exist in the Lake Hazen region.; Breakup of marine-based ice margins between 9 and 8 ka BP led to a retreat of Grant Land Mountain trunk ice, and deglaciation of outermost Hazen Plateau. Plateau ice caps, however, persisted and expanded over highland regions in early Holocene. Between 7 and 6 ka BP, ice retreated to the heads of regional fiords and valleys, after which it remained stable. Breakup of ice within the proto-Lake Hazen basin occurred between 5.3 and 5 ka BP, at which point Grant Land Mountain ice had retreated to near its modern limits.; Diatom abundances serve as a proxy record of summer lake ice cover. Results from the Lake Hazen region indicate a gradual climatic amelioration between 5 and 4 ka BP. The greatest reduction in ice cover occurred between 4 and 3 ka BP, after which, a cooling led to a decline in diatom abundances in higher elevation lakes, while those lower down maintained high levels until ∼2 ka BP.; Basal diamicts in cores from two lakes on Hoved Island records the retreat of formerly grounded ice in central Baumann Fiord ∼9.3 ka BP. Isotopic records of Lobatula lobatulus detail a stepped ice retreat during early to mid-Holocene, beyond the resolution of previous studies of postglacial emergence.