Late Pliocene and Pleistocene reversal of drainage systems in northern Israel: tectonic implications

The arching of the Galilee, northern Israel, is associated with sediment loading in the Dead Sea Transform and Rift. During the Pleistocene, the arching caused the formation of the main North-South water divide in the region and the reversal of stream flow direction. A reconstruction of a main paleochannel which drained large areas in the eastern Galilee to the Mediterranean enabled the determination of age and amplitude of the arching. This reconstruction is based on topographic analysis of thirteen sites containing fluvial remnants in the Beit-Hakerem Valley. We demonstrate that the widespread normal faulting cannot explain the present-day drainage pattern. Dating of basalt clasts from ancient alluvial remnants along the Beit-Hakerem Valley provides a maximum age limit of 1.8 ma to the paleochannel. The Pleistocene tectonism arched the Galilee by 200 m over a wavelength of 40-60 km. A comparison between arched and unarched segments of the rift's margins indicates that fluvial and slope processes on the rift escarpment cannot explain the location and shape of the main water divide. In the Galilee, tectonism is the only factor that controls the formation, location and shape of the main water divide.