Mesoscale and regional kinematics of the northwestern Yalakom fault system: major Paleogene dextral faulting in British Columbia, Canada

Paul J Umhoefer, K. L. Kleinspehn

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

The northwestern Yalakom fault system (YFS) lies on the eastern margin of the Coast Belt in southwestern British Columbia. The Yalakom fault is the most significant structure in the fault system, with at least 115 km of dextral slip, mostly of early Tertiary age. The NW YFS is up to 25 km wide and is bounded on the southwest by the Tchaikazan fault zone, which had 5 km or more of dextral slip. Kinematic and paleostress analysis of mesofaults and map-scale structures shows that secondary faults within the NW YFS had both dextral and sinistral oblique slip. The NW YFS was active from latest Cretaceous(?) to (mainly) Eocene time. Most of the 120 km of dextral slip was transferred to the north via a mosaic of normal and strike-slip faults in central British Columbia. Thus the YFS forms the southwestern margin of a broad zone of transtensional structures that extends to the Tintina-Rocky Mountain Trench fault zone; these structures accommodated northwestward displacement of the northwestern Cordillera in Paleogene time. -from Authors

Original languageEnglish (US)
Pages (from-to)78-94
Number of pages17
JournalTectonics
Volume14
Issue number1
StatePublished - 1995
Externally publishedYes

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ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

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