Geology of the Nicola Group in the vicinity of the Iron Mask batholith, Kamloops, British Columbia.

摘要

Two regional scale deformation events are observed in the Kamloops region. A Late Triassic-Early Jurassic southwest directed compressional event and a later Tertiary extensional deformation episode, manifested in the uplift of the Nicola horst.;A pervasive metamorphic fabric, exposed in the horst and cross-cut by the 144.8 +/- 5.9 Ma LeJeune granodiorite, is interpreted to represent a broad, Middle Jurassic shear zone, formed by east-directed translation of the Nicola arc during contractional tectonics inboard of an east dipping subduction zone. Variations in orientation of the fabric suggest subsequent east-directed compression during post-Jurassic, pre-Eocene deformation.;The Nicola horst is bounded to the northeast by the Cherry Creek Tectonic Zone, a northwest striking fault zone that separates schistose footwall rocks of the Nicola horst from relatively undeformed Nicola Group rocks in the hanging wall. The fault is interpreted to have accommodated multiple episodes of movement associated with both compressional and extensional tectonics.