Latest Quaternary and Holocene paleoceanography of the eastern Baffin Island continental shelf, Canada: benthic foraminiferal evidence

Abstract

Foraminiferal zones, radiocarbon ages on shells, and corrected ages on pretreated organic sediment from four cores from the eastern Baffin Island continental shelf suggest a three-stage deglacial to postglacial history (Late Wisconsin to Holocene). The earliest sediments in the cores contain foraminiferal species (Elphidium excavatum, Cassidulina reniforme, Islandiella helenae) indicative of distal glaciomarine environments that lasted at least several thousand years. An oceanographic change about 8500 years ago is indicated by a Melonis zaandamae zone in northern and central shelf cores collected from 200–800 m water depth. The presence of M. zaandamae in the north and its absence in the south suggest warmer and more saline postglacial water in northern Baffin Bay, whose influence became diluted with cooler coastal meltwater as the current flowed south along the Baffin Island Shelf. Sediments after 6000 years ago on the northern and central shelf are dominated by agglutinated foraminifera, suggesting dissolution of calcareous species. This dissolution event, which affected deeper water cores sooner than cores from the shelf, may be related to the influx of cold, CO2-rich water from the Arctic Ocean during the mid-Holocene. Thus, postglacial oceanographic changes in Baffin Bay appear first in deep northern waters; the lag time in the response to these changes in the shallower water on the shelf and to the south may have been as long as several thousand years.

Quaternary glacial and marine environmental history of northwest Greenland: a review and reappraisal

“…This type of fauna is found in ice-distal sediments in the Canadian Arctic (Osterman and Andrews, 1983;Osterman and Nelson, 1989) and is similar to that found in present assemblages of the Thule area (Phleger, 1952;Feyling-Hanssen and Funder, 1990).…”

Modern Distribution of Benthic Foraminifera From Disko Bugt, West Greenland

“…Other studies of foraminifera in high-latitude fjord and shelf areas have found a range of environmental variables influencing their distribution. Water mass characteristics are commonly identified as important variables, particularly salinity, temperature and dissolved oxygen content (e.g., Schafer and Cole, 1986;Osterman andNelson, 1989, Hunt andCorliss, 1993;Jennings and Helgadottir, 1994;Rytter and others, 2002;Husum and Hald, 2004;Jennings and others, 2004). Other important factors that have also been identified include food supply and substrate texture (Jennings and Helgadottir, 1994;Korsun and Hald, 1998;Husum and Hald, 2004;Jennings and others, 2004); glacial proximity (Nagy, 1984;Vilks and others, 1989;Korsun and Hald, 1998) and duration of sea-ice cover (Schrö der-Adams and others, 1990a, 1990b, Osterman and others, 1999.…”

“…Water circulation and the water masses within Disko Bugt are heavily influenced by the components of the WGC entering the bay from the southwest shown in figure 2 (Andersen, 1981). Due to the relatively shallow nature of the embayment, the colder deeper water within Baffin Bay, the Baffin Bay Deep Water (Osterman and Nelson, 1989), does not penetrate Disko Bugt. Disko Bugt is also influenced by the annual formation of sea ice during December-January and melting by April-May (Andersen, 1981), and significant meltwater flux from coastal glaciers and icebergs.…”

“…In particular, such studies have provided contemporary analogues for paleoenvironmental reconstructions, increasing our understanding of the interaction between climate change and high-latitude environments (e.g., Osterman and Nelson, 1989;Bilodeau and others, 1994;Jennings and others, 1996;Polyak and Mikhailov, 1996;Jennings and others, 2002). There have, however, been few studies of foraminifera from the west Greenland margin.…”

“…Herman and others (1972) investigated foraminifera from southwest Greenland fjord sediments; FeylingHanssen and Funder (1990) investigated the foraminiferal fauna from a number of sections near Thule in northwest Greenland; and Elberling and others (2003) used foraminiferal stratigraphy to investigate pollution in a west Greenland fjord. Studies have tended to concentrate on the east Greenland margin (e.g., Jennings and Helgadottir, 1994;Jennings and Weiner, 1996;Madsen and Knudsen, 1994) and the Canadian Arctic and Arctic Ocean (e.g., Vilks, 1969Vilks, , 1980Vilks, , 1989Osterman, 1984;Schafer and Cole, 1986;Schroder-Adams and others, 1990a;Scott and Vilks, 1991;Bilodeau and others, 1994;Wollenburg andMackensen, 1998a, 1998b). In this paper, foraminiferal, conductivity-temperature-depth profiles (CTD) and sedimentological data are presented from a large marine embayment, Disko Bugt, along the west Greenland margin and the association of faunal assemblages with environmental and sedimentological variables is investigated.…”