LAKE SEDIMENT BASED INSIGHT INTO THE DEGLACIATION AND POST-GLACIAL CLIMATE AND ENVIRONMENTAL HISTORY OF THE MEALY MOUNTAINS, SOUTHEASTERN LABRADOR, CANADA

The Mealy Mountains (53.6° N, 58.6° W) of Southeastern Labrador, Canada are a glacially sculpted mountain range with peaks exceeding 1000 m in elevation, numerous cirques, tarns, and fjord-like lakes. This study presents new sedimentary evidence from lakes in the Mealy Mountains that record the deglaciation and post-glacial history of this little studied region. Basal sediments from multiple lakes include laminated, mineragenic glacial-lacustrine sediment that transitions to organic-rich gytga recording the deglacial to post-glacial evolution of the region. The regional retreat of the Laurentide Ice Sheet is suspected to have occurred between 9,000 and 10,000 calendar years before present. Preliminary basal radiocarbon ages from lakes in the Mealy Mountains place the local timing of the transition to post glacial sedimentation at approximately 6,000 calendar years before present. These dates suggest either the presence of lingering local ice in the uplands of the Mealy Mountains or the possible formation of local mountain glaciers during the early Holocene. Down-core measurements of loss on ignition (LOI), magnetic susceptibility, Rock Eval pyrolysis, and bulk geochemistry from scanning X-ray fluorescence help pinpoint the transition from glacial to post glacial sedimentation and provide additional insight into the post-glacial environmental history of the region.