News & Events

Monday Seminar: Determining millenial-scale variations in sediment sources for N Atlantic ice sheets

Monday, December 04, 2017, 12:15PM - 1:15PM

Speaker

John T. Andrews

INSTAAR/GEOL

Location:

SEEC room S228 (Sievers room)

4001 Discovery Drive, Boulder

Full title

Determining millenial-scale variations in sediment sources for ice sheets in the northern North Atlantic

Abstract

During much of the last glaciation (8 to 110 cal ka BP), large tidewater glaciers drained into the northern North Atlantic Seas.  The question I addressed is whether we can discern differences in sediment provenance that can be associated with specific glacial source areas.  The clearest examples that provides a resounding “yes” are the Hudson Strait sourced Heinrich events, but there are many other ice streams that have been identified as draining the Northern Hemisphere ice sheets.  A variety of methods have been used to identify glacial marine provenance, but here I will use quantitative X-ray Diffraction analysis to evaluate regional and temporal changes in sediment provenance.  I will focus on the GIN Seas and on Baffin Bay and examine the regional mineral assemblages based on ~500 surface samples and which demonstrate clear regional signals.  The data from a series of long piston cores are then evaluated (e.g. MD99-2274, -2280 from the Iceland Sea; MD99-2323 from outh Denmark Strait; HU2013029-077 from the Baffin Is. slope).       

Audience

Free and open to the public.