Sedimentary structural indicators of Arctic terrestrial and aquatic processes

• Main Author: Chutko, Krystopher John
• Other Authors: Geography, Lamoureux, Scott F.
• Format: Thesis
• Language: English
• Published: 2008
• Subjects: Lacustrine sediment; Varves; Microbially induced sedimentary structures; Arctic; Thermal inversion; Subannual laminae; Canada; Devon Island; Archer; Colin Archer Peninsula
• Online Access: http://hdl.handle.net/1974/1220

Thesis (Ph.D, Geography) -- Queen's University, 2008-05-22 09:55:12.184 Annually and subannually laminated lacustrine sediments potentially contain a wide range of information that can be interpreted for paleoenvironmental reconstructions. These laminae are produced by the physical and biological processes that operate in the lake and in the surrounding terrestrial environment. However, identification of the influences that control laminae production may not be straightforward, and other processes may subtly influence the overall depositional sequence. This thesis examines two different depositional environments on Colin Archer Peninsula, Devon Island, Canada, with the objective of identifying the factors that influence subannual sediment deposition and how the resultant sedimentary structures can be used as indicators of paleoenvironmental conditions. In proglacial Lake R, clastic sediment deposition is controlled primarily by subannual meteorological conditions. Periods of positive air temperature or large rainfall events produce discernable laminae that, when combined, form a varve sequence. However, overarching geomorphic controls influence the delivery of sediment to the lake and may reduce or enhance the hydrometeorological signal contained in the varves. An additional influence for calibration of the varve record to meteorological observations is the role that melt season thermal inversions have on temperature extrapolation in the High Arctic. Meteorological stations at sea level may not be representative of the surrounding region, thereby reducing the accuracy of vertical temperature estimation. Investigation of the inversions in the central Canadian High Arctic demonstrated that melt season inversions are common and increased inversion frequency may potentially have influenced enhanced glacial melt since the late 1980s, with implications for proglacial lake sediment transport and deposition. In coastal Lake J, late Holocene sediments record a relatively unusual accumulation of microbially induced ...