TRANSFER OF DISPLACEMENT FROM MULTIPLE SLIP ZONES TO A MAJOR DETACHMENT IN AN EXTENSIONAL REGIME - EXAMPLE FROM THE DEAD-SEA RIFT, ISRAEL

Fabric development and block rotation related to flexural slip were ex amined in sedimentary strata draped over a basement normal fault at th e western margin of the Dead Sea rift in southern Israel, In addition to documenting differences in deformation style as a function of litho logy, this study focuses on the progressive development of flexural-sl ip horizons and fabric development in extensional settings, Deformatio n in the intercalated shale, siltstone, carbonate, and gypsum beds of the Turonian Ora Formation is dominated by extension, bedding-plane sl ip, and block rotation, which occur at different scales and magnitudes throughout the approximately 12 m section, Extension appears as boudi nage in carbonate beds and fibrous sigmoidal gypsum veins in shale, wh ereas strong foliation, highly deformed gypsum veins, and asymmetric f olds characterize slip and adjacent drag zones, Magnitude of extension in individual beds is directly related to relative magnitude of adjac ent bedding-plane-slip horizons, implying a common origin, Initial fle xural slip was lithologically controlled, with displacement occurring along numerous narrow zones throughout shale and siltstone horizons, C ontinued top-to-the-west bedding-plane slip, however, led to antitheti c block rotation within competent beds, which in turn resulted in the termination of slip along zones abutting block-bounding faults, As blo ck size increased during progressive development of flexural slip, so did the spacing between active slip zones, Therefore, rigid block rota tion within subhorizontal simple shear zones provided the mechanism fo r concentrating flexural slip along several major detachments during e xtension of the Ora Formation above a basin-bounding normal fault.