Oran P. Costello

B. Sc. Honours Thesis

Paleoceanographic Reconstruction of the Inner Scotian Shelf During the Younger Dryas: A Benthic Foramineral Study

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Examination of foraminifera from piston core 91-018-53P permits a paleoceanographic reconstruction of the Inner Scotian Shelf, with emphasis on the Younger Dryas cold period. A minimum in the total number of foraminifera and foraminiferal species, and the dominance of Elphidium excavatum forma clavatum characterize the Younger Dryas interval. These results suggest a warm ice margin during the Younger Dryas interval, confirming the presence of a proximal glacial ice mass. The representation of the Younger Dryas in core 91-018-53P, dated at 10,377 to 9,840 14C ybp, is the first well documented and dated marine occurrence on the east coast of North America. Additionally, the core contains the first known marine occurrence of the recently discovered Killarney Oscillation, which represents a minor cold period that pre-dates the Younger Dryas. The late Holocene (represented by Bulimina marginata, Cassidulina laevigata, and Fursenkoina fusiformis as well as peak occurrences of ostracods and planktonic formanifera) and the early post-glacial (represented by Elphidium excavatum forma clavatum, Cassidulina reniforme, and Islandiella teretis) are similar to those previously reported from this area.

Kwywords: foraminifera, paleoceanographic reconstruction, Younger Dryas,
meltwater
Pages: 79
Supervisor: David Scott