Cyclic ductile and brittle deformation related to coseismic thrust fault propagation: Structural record at the base of a basement nappe (Preveli, Crete)

摘要: [1] The structural record at the base of a basement nappe (Preveli nappe, Crete, Greece) thrust upon sedimentary rocks is investigated, aimed on understanding mechanisms which result in decoupling sheet from its original substratum. We identify several superimposed deformation stages, each with characteristic style and indications episodic initially high differential stress. The final stage involves formation matrix supported breccia transected by pseudotachylytes, comprising lowermost 30 m nappe. Brecciation pseudotachylyte occurred single event, structures were not modified afterward. Complete induration composition phengite crystallized during devitrification pseudotachylytes place sequence events into middle crust. propose model relating cyclic stress history to propagation fault limited number seismic events. Terminal brecciation frictional fusion passage front beneath site observation sheet. Absence discernible further consistent negligible basal friction transport as mark switch repeated coseismic loading postseismic relaxation plastosphere, driven approaching fault, passive localized weak plane. For ductile brittle structures, our provides an alternative progressive cooling exhumation concomitant over millions years.