CURRENT PROJECTS
CONTINENTAL TRANSFORMS AND THE DEAD SEA FAULT (DSF)
One of the most intriguing sectors of the seismically-active Dead Sea fault (DSF) is exposed in northern Israel, where dozens of faults and folds crosscut this populated area. Together with A. Sneh, we have mapped these sectors in details and studied their geometry and kinematics. I collaborated with a group of colleagues and post-docs to study the tectonics of the DSF in northern Israel, using a variety of techniques and approaches including meso-structure analysis, seismics, magnetic AMS, and dating. A stratigraphic analysis of Jurassic to Eocene rock units in this area provides ample evidence for a left-lateral offset based on the differences between the two sides of the DSF. Based on seismic data interpretation and plate-motion calculations, we showed that the Hula basin, which was initiated as a pull-apart basin, entered a new geodynamic phase, where a through-going strike-slip fault developed diagonally across the basin in the mid-Pleistocene. A kinematic analysis of meso-structures indicates a change during the Plio-Pleistocene with a northward increasing convergence across the DSF. An application of AMS measurements and analyses reveal similar kinematic indications. In recent years we have extended our area of interest and analyzed the association between the uplift and denudation of Hermon mountain and the activity along the DSF, explored the evolution of the NAFZ and analyzed the tectonics of adjacent rift zones.
Currently, an age framework for the tectonic activity along the DSF is obtained by using U-series ages of striated fault planes and calcite-filled veins (Funded by the BSF and the Government of Israel; collaboration with P. Nuriel and J. Craddock).
SALT TECTONICS
Despite the enormous global interest in salt tectonics, which is largely driven by its importance to hydrocarbon exploration, direct field-based studies of rocksalt exposed at the Earth's surface are rare. Mount Sedom, located at the western side of the Dead Sea Basin, presents one such opportunity for detailed analysis of salt tectonics and structural geology of diapirs in a currently active setting. The study of the diapir was initiated in the 90’s in my M.Sc thesis. With the advance of space geodesy (InSAR, GPS) and the increasing interest in the storage ability of fuel and waste in rock salt cavities, we revisited Mount Sedom and conducted several studies in and around the mountain. We deduced milestones in the uplift history of the diapir, and constructed a mechanical model for growth of an emerging salt diapir in a tectonically active basin. The analytical model helps to constrain the viscosity of rock salt and strain rate during diapirism. We studied the deformation of the “salt mirror” (a fossilized dissolution surface) and reconstructed the Holocene uplift history of the diapir using a variety of field techniques and LiDAR technology. Our fieldwork of salt-wall deformation permits analysis below the limits of seismic resolution (e.g., small-scale fractures), and, hence, allows more rigorous testing of salt tectonic models and mechanisms.
Currently, we are studying the magnetic fabrics of the Sedom sequence in order to use them as proxy to flow and shear strain during diapir emplacement (Funded by the ISF; collaboration with R. Issachar, T. Levi, and I. Alsop)
MAGNETIC FABRICS
Anisotropy of magnetic susceptibility (AMS)-based analysis is used in sedimentary rocks for characterizing petrofabrics and quantifying weak internal deformation. This analysis reveals the magnetic fabrics of rocks, and hence, helps to detect the arrangement (and possibly alignment) of minerals and grains within them. We have applied this method together with supplementary rock-magnetic techniques to solve the kinematics of structures such as clastic dikes, faults, fault-related damage zones, bedding-plane slip surfaces, and fold-thrust systems. The obtained magnetic fabrics also help to reconstruct the strain field next to the Dead Sea Fault. For this, we developed an improved method for isolating the diamagnetic, paramagnetic and ferromagnetic fabrics of the rocks. In terms of rock types, we studied limestone, dolostone, chalk, and lacustrine soft rock (Lisan Formation). The latter rock consists of many structures (e.g., breccia layers, injection structures) that were triggered by paleo-earthquakes in the Dead Sea basin at the late Pleistocene. These ‘seismites’ have different ‘magnetic signatures’ than other structures, facilitating our ability to differentiate between them and ‘passive structures’ unrelated to earthquakes.
The AMS studies are conducted at the rock-magnetic lab in the Geological Survey of Israel. The lab includes high-quality equipment enabling measurements of AMS, AARM, paleomagnetic vectors, and temperature-dependent susceptibility. The aforementioned studies are the results of on-going collaboration with T. Levi, S. Marco, R. Issachar, I. Alsop and D. Elhanati.
Currently, we are studying the magnetic fabrics of the Sedom sequence (see above), and using AMS to quantify the deformation in the Lisan and Zee'im formations.
SOFT-SEDIMENT DEFORMATION
The internal deformation, sequence of events and movement directions of Mass Transport Deposits (MTDs) are key factors in understanding the kinematics and dynamics of their emplacement. We study these aspects in the soft rocks of the Lisan Formation (Dead Sea basin). We studied fold and thrust systems, back thrusts (defined as displaying the opposite vergence to the main transport direction in thrust systems), thrust sequences in gravity-driven fold and thrust belts, sedimentary and structural controls on seismogenic slumping, and co-seismic horizontal slip along bedding-planes.
The studies of MTDs are the results of collaboration with I. Alsop, S. Marco, and T. Levi and is partly funded by the Israeli Government and the ISF.