Fabric transition with dislocation creep of a carbonate fault zone in the brittle regime

Sungshil Kim, Jin-Han Lee, Raehee Han, Nahyeon Kim, Haemyeong Jung

Research output: Contribution to journalArticle

Abstract

Fabric transition by a switch in the dominant slip system of minerals in the plastic regime can be induced by changes in temperature, strain rate, or water content. We propose here this fabric transition by frictional heating in seismogenic fault zones in the brittle regime. The Garam Thrust in the Taebaeksan Basin of South Korea has a hanging wall of Cambrian dolostone juxtaposed against a footwall of Ordovician limestone and records a minimum displacement of ~ 120 m. In a 10 cm thick plastically deformed layer adjacent to the principal slip layer of the fault zone, the lattice preferred orientation of calcite grains suggests that the dominant slip system changes, approaching the principal slip layer, from r 〈02–21〉 and e-twinning, through r 〈02–21〉 and basal 〈a〉 to basal 〈a〉. This fabric transition requires a high temperature-gradient of 40 °C/cm, which we infer to result from frictional heating of the seismic fault zone. We suggest that fabric transition within a thin plastically deformed layer adjacent to the principal slip layer of a fault zone indicates an unusually steep temperature gradient and provides strong evidence of seismic slip.

Original languageEnglish
Pages (from-to)107-116
Number of pages10
JournalTectonophysics
Volume723
DOIs
Publication statusPublished - 2018 Jan 16

Keywords

  • Fabric transition
  • Frictional heating
  • Garam thrust
  • Lattice preferred orientation
  • Seismic slip

ASJC Scopus subject areas

  • Geophysics
  • Earth-Surface Processes

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