Neoproterozoic–early Paleozoic tectonic evolution of Oman revisited: implications for the consolidation of Gondwana

The implications of a new tectonic evolution model that puts Oman at the eastern margin of the Mozambique Ocean during the Neoproterozoic are wide and regionally significant. This model helps understand the Neoproterozoic tectonics and palaeogeography of Gondwana, the closure of the Mozambique Ocean, the palaeogeography of the world-renowned Cryogenian and Ediacaran successions of Oman, and the petroleum systems of Oman and the rest of Arabia. The proposed evolution model implies that the basement of Oman formed at the margin of Neoproterozoic India, and that the Cryogenian–Ediacaran sedimentary succession, and its early tectonic evolution, were separate from those of the Arabian–Nubian Shield to the west (with reference to present-day coordinates through the paper), as they were on opposite sides of the Mozambique Ocean up to the early Cambrian. It also implies that the final Gondwanan suture lies somewhere along, or just west of, the Western Deformation Front, an early Cambrian orogenic belt found in the subsurface of Oman and in outcrops of north and south Oman. Its development is related to Malagasy–Angudan Orogeny, and it separates two realms: the juvenile Ediacaran basement and active margin sedimentary successions of the Arabian–Nubian Shield, and the Tonian igneous and metamorphic basement, Cryogenian rift deposits and Ediacaran passive margin deposits of Oman/Neoproterozoic India. The Precambrian hydrocarbon systems of Oman therefore do not extend to western Arabia, but could extend to India and Pakistan instead. Sediment provenance studies using zircon geochronology and facies maps of the Neoproterozoic successions help to understand the tectonic setting during deposition and the distribution of reservoir rocks in shallow-water settings in NE Oman, and source rocks in deep basinal settings in south and west Oman.