Morphological and structural relations in the Galilee extensional domain, northern Israel

Abstract

The Lower Galilee and the Yizre'el Valley, northern Israel, are an extensional domain that has been developing since the Miocene, prior and contemporaneously to the development of the Dead Sea Fault (DSF). It is a fan-shaped region bounded in the east by the N–S trending main trace of the DSF, in the north by the Bet-Kerem Fault system, and in the south by the NW–SE trending Carmel Fault. The study area is characterized by high relief topography that follows fault-bounded blocks and flexures at a wavelength of tens of km. A synthesis of the morphologic–structural relations across the entire Galilee region suggests the following characteristics: (1) Blocks within the Lower Galilee tilt toward both the southern and northern boundaries, forming two asymmetrical half-graben structures, opposite facing, and oblique to one another. (2) The Lower Galilee's neighboring blocks, which are the Upper Galilee in the north and the Carmel block in the southwest, are topographically and structurally uplifted and tilted away from the Lower Galilee. (3) The southern half-graben, along the Carmel Fault, is topographically and structurally lower than the northern one. Combining structural and geological data with topographic analysis enables us to distinguish several stages of structural and morphological development in the region. Using a semi-quantitative evolutionary model, we explain the morpho-structural evolution of the region. Our results indicate that the Galilee developed as a set of two isostatically supported opposite facing half-grabens under varying stress fields. The southern one had started developing as early as the early Miocene prior to the formation of the DSF. The northern and younger one has been developing since the middle Pliocene as part of the extension process in the Galilee. Elevation differences between the two half-grabens and their bounding blocks are explained by differences in isostatic subsidence due to sedimentary loading and uplift of the northern half-graben due to differential influences of the regional folding.