Abstract: This study describes the structural evolution of the Klondike Schist and the structural setting of mineralized mesothermal veins from which over 500 tonnes of placer gold has been derived. The Klondike Schist was emplaced as a series of thrust slices on top of a structural stack that includes at least three additional thrust slices. A distinctive set of mesoscopic structures, particularly a set of recumbent folds, formed during thrust emplacement. These folds have a general southeast trend, and deform thrust-emplaced ultramafic rocks. Underlying thrust panels contain folds that resemble these thrust-related structures, but have a consistent northeast trend. The Klondike Schist may have
been rotated about a vertical axis during the latter stages of thrusting along phacoidal cleavage zones. Extensional sites in post-thrust kink folds and faults host mesothermal gold veins. Hence, gold mineralization postdated thrust stacking. Normal faults offset mesothermal veins, and host late-stage hydrothermal alteration zones.

Authors: MacKenzie, D., Craw, D., Mortensen, J.K., and Liverton, T.

Keywords: hydrothermal, Klondike Schist, placer gold, Structural Geology

NTS Mapsheet(s): 115O

Citation: MacKenzie, D., Craw, D., Mortensen, J.K., and Liverton, T., 2007. Structure of schist in the vicinity of the Klondike goldfield, Yukon. In: Yukon Exploration and Geology 2006, Emond, D.S., Lewis, L.L., and Weston, L.H. (eds.), Yukon Geological Survey, p. 197-212.

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