Research Article| April 01, 1987 Structural aspects of fluid-rock interactions in detachment zones Stephen J. Reynolds; Stephen J. Reynolds 1Arizona Bureau of Geology and Mineral Technology, 845 North Park Avenue, Tucson, Arizona 85719 Search for other works by this author on: GSW Google Scholar Gordon S. Lister Gordon S. Lister 2Bureau of Mineral Resources, Canberra 2601, Australia Search for other works by this author on: GSW Google Scholar Author and Article Information Stephen J. Reynolds 1Arizona Bureau of Geology and Mineral Technology, 845 North Park Avenue, Tucson, Arizona 85719 Gordon S. Lister 2Bureau of Mineral Resources, Canberra 2601, Australia Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1987) 15 (4): 362–366. https://doi.org/10.1130/0091-7613(1987)15<362:SAOFII>2.0.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Stephen J. Reynolds, Gordon S. Lister; Structural aspects of fluid-rock interactions in detachment zones. Geology 1987;; 15 (4): 362–366. doi: https://doi.org/10.1130/0091-7613(1987)15<362:SAOFII>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Metamorphic core complexes and associated detachment faults of the North American Cordillera represent gently dipping, normal-displacement shear zones (detachment zones) along which hot, deeper levels of the crust were transported upward and outward from underneath a brittlely distended upper plate. Structures that formed during the ductile-to-brittle evolution of detachment zones can be used to reconstruct the relative magnitudes of fluid pressure and deviatoric stress at different levels within the shear zones. Mylonitization, which occurred along deeper segments of detachment zones below the brittle-ductile transition, was locally accompanied by tensile failure, indicative of low deviatoric stress and high fluid pressure. This condition persisted into the earliest phases of brittle deformation, after which shear fractures formed due to both a reduction in fluid pressure and an increase in deviatoric stress. Brittle deformation of upper-plate rocks occurred largely under conditions of low fluid pressure.Structural and geochemical data suggest that normal displacement on detachment zones results in establishment of two fluid systems: (1) an upper-plate system driven by convection and dominated by meteoric and connate fluids at near-hydrostatic pressures and (2) a system within deeper levels of the shear zone, where fluids are largely derived from igneous sources and fluid migration is aided by dilatancy pumping. The late phases of normal displacement on detachment zones structurally juxtaposed rocks affected by the two fluid systems and locally caused the shear-zone rocks to be overprinted by mineralization related to the upper-plate fluid system. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
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Reynolds et al. (1987) studied this question.