Abstract: The Aishihik Batholith is comprised of foliated and lineated, equigranular hornblende granodiorite and crystallized at about 216 Ma. The batholith is in contact to the west with a metamorphic terrane of continental affinity. However this contact lacks intrusive features common to the margins of most granitic batholiths. In addition, rocks adjacent to the contact are mylonitized and ductiley deformed. These relationships suggest that the Aishihik Batholith does not intrude the adjacent metamorphic terrane, but is allochthonous above it. Kinematic indicators are consistent with the Middle Jurassic quartz monzonite plutons cutting the detachment implying that tectonism occurred during, or prior to the Early Jurassic. The significance and regional extent of this detachment remains a matter of conjecture. The batholith, part of the Stikine volcanic arc, may have originally intruded the metamorphic terrane. Tectonic modification of this relationship could have occurred during collision of Stikinia with North America. Alternatively, Stikinia may be far travelled with respect to the batholith.

Authors: Johnston, S.T.

Citation: Johnston, S.T., 1988. The Tectonic Setting of the Aishihik Batholith, SW Yukon. In: Yukon Geology Volume 2, J.G. Abbott (ed.), Exploration & Geological Services Division, Indian & Northern Affairs Canada, p. 37-41.

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