The low-angle, eastward-dipping Kettle River fault has been mapped for >45 km along the eastern flank of Kettle dome. The fault juxtaposes lower-plate, mylonitic, sillimanite-grade metamorphic rocks against upper-plate, greenschist-grade metamorphic rocks and unmetamorphosed but folded Eocene volcanic and sedimentary rocks. The geometry of high-angle listric(?) faults, which cut upper-plate rocks, suggests that the upper plate moved eastward relative to the lower plate. Cataclasis and chloritization spatially related to the Kettle River fault cut the mylonitic foliation in the lower plate, indicating that the gneisses in the lower plate were not part of a hot, mobile diapir during at least the latest stage of their “emplacement.” The similarity of the Kettle River fault to the folded Newport fault along the northern contact of Spokane dome suggests that these faults postdate the mylonitization of the lower plate but predate regional doming.

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