MSc student Leigh van Drecht completed her second field season in the Whitehorse trough, central Yukon, and investigated fluvial to deep-marine strata that document synorogenic sedimentation during the early development of the North American Cordillera. This work is part of our “Tectonics and paleogeography of ancient orogens” research program. Leigh’s 2017 fieldwork focused specifically on the physical stratigraphy and depositional age of rock units at the Upper Triassic Lewes River Group- Lower Jurassic Laberge Group contact. Detrital zircon (U-Pb & Hf isotope) studies of basal Laberge Group rocks will reconstruct the source-to-sink history of the Whitehorse trough and constrain the crustal evolution of adjacent source terranes. Leigh will present her field results and preliminary detrital zircon U-Pb and Hf isotope data at the GSA Annual Meeting in Seattle, Washington in October 2017. This work is supported by the Yukon Geological Survey and NSERC.
Summer 2017 fieldwork by Luke Beranek focused on lower Paleozoic volcanic and sedimentary rocks in the Clements Markham and Northern Heiberg fold belts, Canadian Arctic Archipelago. Field studies were conducted as part of the German Federal Institute for Geosciences and Natural Resources CASE 19 (Circum-Arctic Structural Events) expedition to northern Ellesmere Island. The goal of this research is to constrain the origin and tectonic significance of rock units that crop out between the allochthonous Pearya terrane to the north and Laurentian parautochthon to the south. Paleozoic rocks within these fold belts have uncertain origins, but some existing scenarios involve: (1) Ordovician arc-related origins between Pearya and the Franklinian margin; (2) Ordovician arc-related origins along the Iapetan margin, with later transport from NE Laurentia to Ellesmere Island by strike-slip faulting; and (3) Silurian continental arc-related origins along the Franklinian margin. New studies in the Kulutingwak Fiord region of Ellesmere Island and Svartevaeg Cliffs of Axel Heiberg Island were initiated to investigate these scenarios and test hypotheses for circum-Arctic tectonics.
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