Provenance of Heinrich layers in core V28-82, northeastern Atlantic: 40Ar/ 39Ar ages of ice-rafted hornblende, Pb isotopes in feldspar grains, and Nd–Sr–Pb isotopes in the fine sediment fraction

Abstract

Several correlatable layers of sediment, rich in ice rafted grains, have been documented in the North Atlantic. The most notable within the last glacial cycle are the Heinrich layers, layers extremely rich in ice rafted detritus and generally barren of foraminifera within the North Atlantic ice rafted detritus (IRD) belt. The view of these layers is that they represent events where great armadas of icebergs were launched into the North Atlantic. The importance of the Heinrich layers lies in their connection with abrupt climate change in the North Atlantic, and perhaps globally. There is a growing number of published provenance studies of the Heinrich layers in the North Atlantic, based on a variety of methods. However, there is little overlap of methods applied to the same samples. In this contribution, we present a multi-component provenance study of Heinrich layers H1, H2, H4 and H5 from core V28-82 in the eastern North Atlantic. Our results indicate that virtually the entire inventory of terrigenous clastic detritus in Heinrich layers H2, H4 and H5 came from ancient continental sources surrounding the Labrador Sea. Although Heinrich layer H1 is similar in many respects, it appears to have some significant differences relative to the other three.