Dating fault reactivation by Ar/Ar laserprobe: an alternative view of apparently cogenetic mylonite-pseudotachylyte assemblages.

Watts, L. M; Sherlock, S; Holdsworth, R. E; Roberts, D

Abstract

Apparently cogenetic mylonite–pseudotachylite assemblages are commonly reported in major fault zones. They represent two very incompatible modes of deformation, and complex formation mechanisms have been proposed to explain this paradox. We report here one such assemblage from Central Norway in which apparently synchronous mylonite and pseudotachylite formation is separated by 100 Ma-mean muscovite Ar/Ar laserprobe spot ages from mylonite, and pseudotachylite matrix, are 406 ± 11 Ma and 290 ± 10 Ma respectively. In preference to a complex cogenetic model we invoke fault reactivation as a viable alternative, and suggest that assumed contemporaneity in such assemblages may be invalid in many cases.

Citation

Watts, L. M., Sherlock, S., Holdsworth, R. E., & Roberts, D. (2004). Dating fault reactivation by Ar/Ar laserprobe: an alternative view of apparently cogenetic mylonite-pseudotachylyte assemblages. Journal of the Geological Society, 161(3), 335-338

• Journal Article Type: Article
• Acceptance Date: Jan 8, 2004
• Online Publication Date: Mar 3, 2017
• Publication Date: 2004-05
• Journal: Journal of the Geological Society
• Print ISSN: 0016-7649
• Electronic ISSN: 2041-479X
• Publisher: The Geological Society
• Peer Reviewed: Peer Reviewed
• Volume: 161
• Issue: 3
• Pages: 335-338
• Public URL: https://durham-repository.worktribe.com/output/1596974