A significant missing component in paleo-reconstructions of Greenland Ice Sheet (GIS) behavior has been the lack of an unambiguous ice sheet tracer. The development of such a tracer for the GIS retreat and aerial extent is proposed using terrigenous provenance markers and the different bedrock terrane ages of southern Greenland (Archean versus varying Proterozoic ages). Specifically, streams will be sampled for suspended load sediment from the geologic terranes of southern Greenland. Suspended load sediment will be measured for trace-element and Sr-Nd-Pb isotope composition, and magnetic properties of the sediment will be determined. These data will be compared with previously made and new measurements on a core off of southern Greenland from a well-studied sediment sequence spanning the last 430 kyrs and 5 interglacials. Isotope studies on piston core samples will focus on the silt size fraction in order to minimize the influence of far traveled clay size sediment. Ice rafted sediment will also be avoided. Trace element records combined with previous and newly obtained magnetic records will provide estimates of the response time of the southern GIS to a warming climate by identifying the timing and duration of ice sheet retreat. The Sr-Nd-Pb isotope tracers will allow calculations of sediment sources and when ice retreated off portions of southern Greenland, thus estimating its contribution to higher sea levels.
- Brian Beard - UW-Madison
- Joe Stoner - Oregon State
GRADUATE STUDENTS
- Lisa Colville (finished M.S.)
- Kelsey Winsor