Normal fault systems within extensional domains often form steep mountain fronts by repeated seismic events, with substantial topography leading to colluvial breccia accumulation at the base of the slope on the hanging-wall. The growth of relief in these tectonically active areas is controlled by the interactions between tectonics and surface processes. This study investigates the Zurim Escarpment, a major normal-fault system in northern Israel, focusing on the Sajur Fault segment. We examine the long-term evolution of the escarpment by analyzing two long-lived morphologic markers of fault activity: 1) the mountain front geometry and lithology, and 2) the associated colluvial breccia, which exhibits several deposition generations.
We integrate U-Pb dating of calcite precipitates in the breccia, OSL/TT-OSL dating of quartz grains in the breccia matrix, and in-situ cosmogenic 36Cl accumulation in the escarpment's carbonate bedrock to reconstruct slip rate and link breccia deposition with fault activity. Using a forward numerical MATLAB model, we simulate 36Cl concentrations on the mountain front to reconstruct long-term morphotectonic rates beyond the temporal limitations of fault scarp exposure dating. The model results indicate an elevated long-term erosion rate averaging glacial and interglacial periods, with enhanced erosion during glacial phases. U-Pb dating of calcite precipitates constrains the age of the older breccia phase to ~2.5 Ma and TT-OSL dating constrain the younger phase to at least 1.1 Ma. By combining clast provenance analysis with constraints on the breccia age, we calculate a long-term slip rate of 0.07-0.13 mm/year over the past 2.5 Ma, similar to a rate of 0.09 mm/year for the past 130 Ka given by ³⁶Cl cosmogenic modeling. These rates are lower than the short-term rate of 0.23 mm/year documented for the past 30 Ka, reflecting that slip rates stabilize over longer time scales as they capture the complete ratio of active to quiescent periods.