Evolving deformation along a transform plate boundary: Example from the Dead Sea Fault in northern Israel

Abstract

We analyzed geologic structures adjacent to the Dead Sea Fault (DSF) along the margins of the Sinai and Arabian plates in northern Israel in order to investigate the style and sequence of deformation associated with a transform plate boundary. The field area, located between the Hula basin in northern Israel and the Lebanese restraining bend in southern Lebanon, is divided into distinct structural blocks by a series of distributed faults that comprise this approximately N‐S trending section of the DSF. Cretaceous and Tertiary rocks within and adjacent to the structural blocks are folded into broad anticlines and synclines, with more intense localized shortening manifested by tight folds and thrust duplexes. Kinematic analyses of folds, faults, and veins provide evidence for two directions of regional shortening: (1) NW‐SE shortening responsible for the formation of NE‐SW trending fold axes and left‐lateral strike‐slip motion along N‐S trending faults and (2) E‐W shortening as indicated by N‐S trending fold axes, N‐S striking thrust faults, and extensional calcite‐filled veins that strike E‐W. Crosscutting relations and U‐Th ages of the vein material suggest that the E‐W phase of transform‐normal shortening represents the most recent and presently active phase of deformation. The structural analysis provides evidence for the transition from an early (Miocene–lower Pliocene) phase of pure strike‐slip motion to a late (Pleistocene to Recent) phase of convergent strike slip. The latter phase is characterized by strain partitioning, which is manifested by discrete left‐lateral strike‐slip motion across weak N‐S faults and the development of a fold‐thrust belt in response to transform‐normal shortening. Analogous to the strain partitioning observed in southern California, we suggest that blind thrust faults adjacent to the DSF in the study area may pose a seismic risk to populations in northern Israel and southern Lebanon.

Formation of fault-related calcite precipitates and their implications for dating fault activity in the East Anatolian and Dead Sea fault zones

“…The east -west orientation of the Har Zefiyya dilation veins reflects a local north -south extension. This deformation is not consistent with normal dip-slip or reactivated reverse movement along the SE-dipping Har Zefiyya Fault (Weinberger et al 2009). However, the formation of such a dilation vein system may represent a stage in deformation that was associated with a regional approximately north-south extension and roughly east -west contraction, as evident in other sites along this sector of the DSFZ (Weinberger et al 2009).…”

“…This deformation is not consistent with normal dip-slip or reactivated reverse movement along the SE-dipping Har Zefiyya Fault (Weinberger et al 2009). However, the formation of such a dilation vein system may represent a stage in deformation that was associated with a regional approximately north-south extension and roughly east -west contraction, as evident in other sites along this sector of the DSFZ (Weinberger et al 2009). Calcite-filling dilation veins have precipitated both a short or a long time after the initial opening, and are most probably controlled by the local hydraulic system.…”

“…The UTh age results, although close to the limit of the method, indicate that the initial opening of the vein occurs prior to 550 ka, with continued calcite growth until 510-550 ka. Weinberger et al (2009) suggested that a significant component of eastwest regional shortening, normal to the DSFZ, occurred during the late Pleistocene. It is possible that the onset of this deformation stage, prior to 550 ka, is represented by the formation of dilation veins in the Har Zefiyya Fault Zone.…”

“…1c) in the hanging wall and the Deir Hanna Formation (Cenomanian; Kudk in Fig 1c) in the footwall (Sneh & Weinberger 2003). Kinematic indicators suggest a younger reverse motion occurred along this fault (Weinberger et al 2009). There are no age constraints on fault activity; however, calcite separates from fault-plane slickolites have been analysed by U -Th geochronology and found to be older than the age limit of the method, which suggests ages older than 500 ka (Bar-Matthews & Weinberger unpublished data).…”

Early-to-mid Pleistocene Tectonic Transition Across the Eastern Mediterranean Influences the Course of Human History

“…Further south a general tendency of fault localization towards the axis of the Dead Sea fault is recorded along the margins of the Gulf of Elat (Aqaba; Marco, 2007). This differential lateral motion along the entire Dead Sea fault, extensional in the south as opposed to contractional in the north, result from a change in relative plate motion which developed during the early Pleistocene (Schattner and Weinberger, 2008;Weinberger et al, 2009). …”