Ali Engin Aksu
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M. Sc. Thesis
The Late Quaternary Stratigraphy and Sedimentation History of Baffin Bay
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Twenty-six piston and 12 gravity cores from deep water in Baffin Bay and Davis Strait have been examined. Five facies were identified. Apparently hemipelagic muds occur at the surface and at several depths within the cores. Gravelly sandy muds and muds, rich in detrital carbonates, are common on the abyssal plain and Baffin Island rise. This facies thins to the east and south. Gravelly sandy muds with little carbonate occur in slope and rise cores off Baffin Island and Greenland. Thin beds of red sandy mud are very common in central Baffin Bay and the Baffin Island slope. Graded sand and silt beds are the dominant lithology of southern Baffin Bay and Davis Strait. Most appear to be turbidites. Many of the gravelly sandy muds occur in graded beds and are interpreted as resedimented debris flows or turbidites. Some may be directly ice rafted.
The cores were correlated lithologically. This correlation was confirmed by the occurrence and abundance of biogenic tests, the presence of two levels of volcanic ash, and paleomagnetic properties. The ash horizons were correlated with North Atlantic ash zones dated at 9,300 yr. BP and 65,000 yr. BP by Ruddiman and Glover (1972, 1975). Two amino acids dates were also used to establish the age of the age of the sediment sequence. One major excursion of the earth's geomagnetic field was identified. Extrapolated dates suggest this occurred between 25,000 yr,. BP and 35,000 yr. BP.
A climatic curve was established on the basis of abundance and occurrence of dextral and sinistral G. pachyderma, and total biogenic material. The results indicate an interglacial period with conditions similar to the present at the base of one core. Extrapolated dates assuming a constant rate of sedimentation suggest a Sangamon age. This is followed by several stadials and interstadials, and followed by a warming to present conditions.
The Holocene sediments were accumulated at 5 cm to 6.6 cm/1000 yr. and Wisconsin sediments at 7.3 cm to 9.1 cm/1000 yr.
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Supervisor: D. J. W. Piper