CGRG Bibliography of Canadian Geomorphology
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Author : Gosse, J.; Yaehne, S.; Young, M.; Taylor, K.; Stübner, K.; Margreth, A.; Hidy, A.; Novak, A.; Stockli, D.; Centeno, J.; Utting, D.; Rybczynski, N.
Date : 2011.
Title : Landscape evolution of the Eastern Arctic Rim, Canada.
Publication : Joint Annual Meeting of Geological Association of Canada, the Mineralogical Association of Canada, the Society of Economic Geologists and the Society for Geology Applied to Mineral Deposits. May 25-27, 2011. University of Ottawa, Ottawa, Ontario.
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Abstract
The Eastern Arctic Rim extends from the Torngat Mountains of northern Labrador, along eastern Baffin and Devon Islands, to Ellesmere Island. Knowledge of the landscape evolution of the rim during and since rifting from Greenland has been indirectly derived from variations in sediment fluxes deduced from marine geophysical and sediment records, from chronology and interpretation of the Cape Dyer volcanic field, and from thermal and geodynamical models of rifting and margin subsidence. Besides the ECSOOT transect across the Torngat Mountains, no land-based crustal dynamics data exist. Timing of initial rifting, symmetry of rifting, relationship between volcanic vs non-volcanic margins and flank evolution, and roles of crustal roots on exhumation and rock uplift of the rim have remained intractable until now. From Labrador to Devon Island, apatite and zircon (U-Th-Sm)/He measurements in over 200 samples collected along strategically oriented horizontal (margin parallel and perpendicular) and vertical transects, and randomly throughout the islands allow us to identify the location of crustal roots, establish rates of tilting and exhumation of the physiographic provinces, timing of drainage development, and the style of post-uplift flank evolution. In the Torngat Mountains, rift flank uplift began at 150 ± 10 Ma, based on a 1400 m vertical transect, less than 10 Ma before the earliest sea floor spreading (Alexis Fm basalts and Bjarni Fm sediments). The two margin-parallel transects indicate a pre- or syn-Jurassic fluvial drainage controlled today’s fjord spacings. The margin perpendicular transect reveals significant west-down tilting across the entire Ungava Peninsula, and rates of exhumation are fastest near the highest peaks (up to 100 m/Ma over a 10 Ma period), supporting a pinned-divide exhumation model. In the North Central Baffin region, a pinned divide model is supported in the Foxe Basin-Baffin Bay horizontal transect, although rates of exhumation differ across the faults bounding the five physiographic provinces. Cooling ages in the Bruce Mountains vertical transect all pre-date the late Cretaceous and indicate a slow gradual cooling since the Jurassic, revealing that this part of the rim lacks a crustal root that would have provided the buoyancy to accelerate rift flank uplift. Samples collected on Cumberland and Hall Peninsulas and eastern Devon will help locate other crustal roots and establish the history and style of exhumation along the margin. The ultimate goal is to link the thermochronology to marine sediment and geophysical records for an improved understanding of the rift and post-rift history of the rim.
Bibliography of Canadian Geomorphology