LATE QUATERNARY MARINE AND TERRESTRIAL ENVIRONMENTS, NORTHWESTERN BAFFIN-ISLAND, NORTHWEST-TERRITORIES

Paleoenvironmental data were analyzed from terrestrial, lake, and mari ne sediments collected near Arctic Bay, Baffin Island, N.W.T. Eighteen new radiocarbon dates provide chronological control, superseding earl ier results. Spuriously old dates were obtained from both sandy peats and low-organic lake sediments. The most reliable dates were from mari ne shells and foraminifera. They indicate that deglaciation was underw ay by 9000 BP rather than 16,000 BP. Over the period of the record, th e local environment was characterized by a high arctic pollen assembla ge dominated by grass, sedge, and willow; a middle Holocene warm perio d is indicated by increased willow, herb, and moss values. Sea-ice con ditions were severe enough to inhibit the growth of diatoms until ca. 6300 BP and ice proximal and deglacial conditions prevailed in the fio rds until ca. 6000 BP. Diatom productivity increased between 3000 BP a nd 2500 BP, suggesting warmer surface waters and less sea ice. After 2 000 BP diatom accumulation decreased sharply, due to a cooling of clim ate. The foraminifera indicate a major change in bottom water conditio ns ca. 4000 BP as the benthic species shift from a calcareous to an ar enaceous assemblage.