Abstract

Radiocarbon dates from marine piston cores and from onshore raised marine stratigraphic sections in the Hudson Strait region were used to reconstruct deglacial isochrons for 9900, 9500, 8800–8500, and 8000 BP. At the culmination of the Gold Cove readvance (9900 BP), Labrador–Ungava ice flowed northeastward across Hudson Strait and outer Frobisher Bay and stood for the last time on the Baffin Island continental shelf. Subsequent retreat by calving was rapid and profound, opening the entire Hudson Strait marine trough by 9500 BP. At this time, ice dispersal from Foxe Basin, Labrador–Ungava, and local ice on Meta Incognita Peninsula supported tidewater margins along much of the coastline, with the exception of northernmost Ungava Peninsula, where the ice margin stabilized onshore. This onshore margin remained in place throughout the Cockburn Substage while a major northeastward readvance of Ungava Bay ice (the Noble Inlet readvance from 8800 to 8500 BP) crossed outer Hudson Strait, grounding on the Hudson Strait sill and the south coast of Meta Incognita Peninsula. Sedimentation continued in an enclosed basin in western Hudson Strait, but marine circulation was prohibited by the ice dam, and upper water column salinities became too low to support a marine molluscan fauna. Ungava Bay ice was not thick enough to sustain flow across eastern Hudson Strait, and rising sea levels soon destroyed the Noble Inlet ice dam. By 8300 BP normal marine waters were circulating in eastern Hudson Strait, followed shortly thereafter (at 8100 BP) by the deglaciation of western Hudson Strait and Hudson Bay.

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