Crustal structure of the United Arab Emirates and northern Oman Mountains from constrained 3D inversion of gravity and magnetic data: The Moho and basement surfaces

Abstract

The Moho depths of the United Arab Emirate (UAE) and northern Oman mountains estimated from the gravity data assuming general local isostasy deepens from 34–38 km in the western and central areas of the UAE, and reaches 32–36 km and 40–52 km in the foreland basin and Oman-UAE mountains, respectively. To image the morphology of the basement, we performed 3D inversions of gravity and aeromagnetic data constrained by seismic and well data within the sedimentary layer. The inverted susceptibility and density models are generally consistent with each other. They both show that the basement, in most of the UAE, is covered by 8–18 km of sediments with the deepest part occurring within the foreland basin that flanks the western side of the Oman-UAE mountains. Farther west, covering the remainder of the UAE, the gravity and magnetic basement models vary significantly. The basement morphology derived from the density model probably reflects metasediments of weakly to non-magnetic basement with a broad basement high trending SE-NW from the Lekhwair high in the southeast to the northwestern offshore of the UAE that may delineate the present-day position of the flexural bulge caused by loading of the Semail ophiolite. In contrast, the basement morphology derived from the susceptibility model is both smoother and deeper from the west-central of the UAE to the western margin of the foreland basin, which could reflect a deeper magnetic crystalline basement. Moreover, the susceptibility model revealed several magnetic bodies with high susceptibilities interpreted as intra-basement blocks or igneous intrusions.