Abstract: Bedrock mapping of parts of the Whitehorse and Teslin map areas in the summer of 2012 has improved upon existing knowledge of the local geology from previous 1:250 000 scale mapping in the respective map sheets. Our mapping characterizes the nature of the Cache Creek terrane in Yukon, including the identification of a previously unknown siliciclastic package, informally named the Michie formation, a gabbroic intrusive complex, and the Marsh Lake intrusive complex, in addition to more typical oceanic lithologies. This mapping helps refine the structural history of the area and define the relationships between Cache Creek terrane and rocks of Stikinia and Whitehorse trough. Two main phases of compressional deformation have been identified: 1) an initial phase of west-verging thrusting, emplacing Cache Creek terrane rocks above rocks of Stikinia and the Whitehorse trough along the Judas Mountain thrust, a northern equivalent to the Nahlin fault; and 2) a subsequent, second phase of thrusting which reshuffles Stikinia and Whitehorse trough rocks onto the Cache Creek terrane along the east-verging Mount Michie thrust. Three main styles of mineralization were observed, associated with either ultramafic bodies or Cretaceous intrusions in the region.

Authors: Bickerton, L., Colpron, M. and Gibson, D.

NTS Mapsheet(s): 105C, 105D

Citation: Bickerton, L., Colpron, M. and Gibson, D., 2013. Cache Creek terrane, Stikinia, and overlap assemblages of eastern Whitehorse (NTS 105D) and western Teslin (NTS 105C) map areas. In: Yukon Exploration and Geology 2012, K.E. MacFarlane, M.G. Nordling and P.J. Sack (eds.), Yukon Geological Survey, p. 1-17.

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