Magnificent marine mud : a late Foxe paleoclimate record from Outer Frobisher Bay and Brevoort Basin, Baffin Island, Canada
Hooyer, Thomas S.
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High resolution seismic reflection data and three piston cores from Frobisher Bay and Brevoort Basin were examined to further refine the positions of late glacial ice margins and the deglacial chronology of this region. The seismic data reveals three acoustic units similar to those recognized on the southeast Baffin Island continental shelf (Evans, 1990 and Praeg et al, 1986) and the Labrador shelf (Josenhans et al, 1986). In Frobisher Bay, turbidtes originating form a glacial marine source make up the majority of the sediment which is distributed among five small basins adjacent to Griffin Bay/Ney Harbor, Charles Francis Hall Bay, York Sound, Jackman Sound, and the Savage Islands. Sediment deposition within the basins is controlled by bedrock topography of the seabed as well as an available sediment source from the adjacent Meta Incognita Peninsula. Detailed sedimentological data of the lithostratigraphic units within piston cores 007 and 009 (York Sound Basin), indicate a sediment source associated with the retreating local ice caps and foreign ice of the Noble Inlet and Gold Cove readvances. This is confirmed by cores collected from the basins adjacent to Griffin Bay/Ney Harbor (Duvall, 1993) and the Savage Islands (Stravers et al, 1992). . In Brevoort Basin (to the east of Hall Peninsula), seismic reflection profiles show a sequence of post-glacial and glacial marine sediments overlying a acoustically chaotic unit that is interpreted as either a subglacial till or debris flow deposit. Two small moraines on the southwest margin of the basin ABSTRACT appear to be correlative to glacial marine sediments deposited within the basin (Kaufman et al., 1993). The sedimentary record from piston core (022), collected from the basin reveals an ice marginal retreat sequence (9.9-7.7 yrs BP.) grading slowly into post glacial sediments (7.7-2.4 yrs BP.). This sequence is attributed to the initial retreat of the Gold Cove ice margin (by 9700 yrs BP) from the Hall Peninsula continental shelf, and lingering glacial input from local ice on Hall Peninsula.