Reconstructing Pleistocene Ocean Currents near Southern Greenland Based on Foraminiferal Assemblages

Presenter

Dakota Ishutina

Campus

UMass Amherst

Sponsor

Isla S. Castañeda, Department of Earth, Geographic and Climate Sciences, UMass Amherst

Schedule

Session 1, 10:30 AM - 11:15 AM [Schedule by Time][Poster Grid for Time/Location]

Location

Poster Board A47, Campus Center Auditorium, Row 3 (A41-A60) [Poster Location Map]

Abstract

Changes in ocean currents have a significant effect on Greenland and its ice sheet, with warm currents increasing melting rates and depositing large amounts of freshwater into the polar ocean. Reconstructing past temperatures and environments from the Pleistocene can allow us to understand how Arctic Ocean and Northern Atlantic currents have shifted alongside sea surface temperatures (SSTs) during periods of rapid glaciation and deglaciation. In this study, we examine Pleistocene sediments from ODP (Ocean Drilling Program) Site 647 from the southern Labrador Sea for microfossil assemblages. Foraminiferal species were assessed in 44 samples spanning 2.577 Ma to 0.228 Ma, to track changes in the currents influencing the Site (North Atlantic Current, Irminger Current, Labrador Current). Throughout the Pleistocene, notable changes in the foraminiferal assemblages occur with older parts of the core (≥2.416 Ma) being barren. The record shifts to consistently warm currents, increasing N. incompta, around ~1.508 Ma and later, while the younger parts of the core are dominated by N. pachyderma suggesting colder conditions. There is a significant drop in N. pachyderma to 16.5% with an increase in species diversity at 0.296 Ma. Analyzing the observed shifts in the assemblages provides crucial information about how ocean currents behaved during times of global warming and cooling throughout the Pleistocene which can allow us to interpret how these same water masses may shift in the near future with anthropogenic forcing increasing global temperatures.

Keywords

paleoclimate, foraminifera, Pleistocene, Arctic, ocean currents

Research Area

Geology and Earth Sciences

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