LAMINATED SEDIMENTS AND PALEOENVIRONMENTAL RECONSTRUCTION IN THE CENTRAL CANADIAN ARTIC ARCHIPELAGO NUNAVUT, CANADA

In order to gain a greater understanding of recent climatice changes in the Canadian arctic, laminated sediments were recovered from Cape Hurd Lake in the central Canadian artic archipelago, Nunavut, Canada. The laminated sediments are likely varves and thus may record distinct seasonal and interannual changes in hydrology, limnology and ultimately past climate. Cape Hurd Lake is fed by two inlet streams and influenced by the ablation and accumulation of an adjacent ice cap. Cape Hurd is a meromictic, flat-bottomed lake at sea level and is ideal for the preservation of laminations. As a result, the laminations or varves, which are preserved, serve as an accurate paleoenvironmental indicator because the laminations reveal information about the local biologic, geochemical and sedimentological processes in response to seasonal fluxuations. The study focuses on a detailed analysis of thin sections taken from cores retrieved from Cape Hurd Lake during May of 2000 and the summer of 1999. The goal of the study is understand the pattern of laminated sediment variability observed in the thin sections, which are driven by changes in temperature, precipitation, ice cover, glacial retreat and advance through the late Holocene. This will be undertaken through the detailed examination of grain structure and chemical composition of the lamina using petrographic microscopy and SEM-EDS for detailed structural and compoisitional variability. Specific attention will be paid to variability in the last millenium where short term events such as the Little Ice Age and the 20th Century warming may be detected by changes in structure and composition of the laminated sediments.