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 language | English |
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Pages (from-to) | 107-116 |
Number of pages | 10 |
Journal | Tectonophysics |
Volume | 723 |
DOIs | |
Publication status | Published - 2018 Jan 16 |
Bibliographical note
Funding Information:We thank Nicola De Paola and Janos Urai for their comments which improved the manuscript. We also thank Co-Editor-in-Chief, Kelin Wang, for his editorial effort and encouragement. This work was supported by the National Research Foundation of Korea fund NRF-2014R1A1A2056836 to Ree.
Publisher Copyright:
© 2017 Elsevier B.V.
Keywords
- Fabric transition
- Frictional heating
- Garam thrust
- Lattice preferred orientation
- Seismic slip
ASJC Scopus subject areas
- Geophysics
- Earth-Surface Processes