Multi-proxy records of environmental changes in Hudson Bay and Strait since the final outburst flood of Lake Agassiz-Ojibway

摘要

In this study postglacial continuous high-resolution data from five marine sediment cores from Hudson Bay and Hudson Strait are presented. Up to now studies in this area focused on the distinction between large scale climatic variations like the glacial-postglacial transition or most recent processes. However, as demonstrated in this study, using sedimentological, geochemical and geophysical parameters, postglacial sediments provide provenance signals distinguishing between Proterozoic Dubawnt Group sediments, Paleozoic limestone sources underlying parts of Hudson Bay and Strait and Precambrian granitoids from the Canadian Shield. For example it is shown that redistribution of Dubawnt Group sediments is of minor importance after the outburst flood of Lake Agassiz. Paleoproductivity indicators also give insights into paleotemperature trends. These are in phase with terrestrial reconstructions from that area. Colder conditions in Hudson Strait until ca. 4500 cal BP followed by a signal of warmth until ca. 4000 cal BP are suggested. Subsequently, a cool interval lasting until approximately 2000 cal BP occurred. Thereafter, a gradual decrease in temperature was observed reaching lowest values during the Little Ice Age period and increasing again afterwards.