Petrology and geochronology of a Neoproterozoic dyke swarm from Marbat, South Oman

The calc-alkaline geochemistry of the basement gneisses and intrusive suite into which the Marbat were intruded suggest analogy with the Al-Bayda island arc terrane in Yemen. Fracture pattern analysis from Marbat suggests that intrusion of the major swarm may be related to sinistral strike-slip faulting caused by regional east-west compression. A similar stress regime can also explain the orientation of the Mukeras dyke swarms of the Al-Bayda terrane. Additional geochronological data from Marbat and the Hallaniyat Islands imply the existence of a second phase of dyke intrusion at ∼600 Ma which is again similar to the situation prevailing in the Al-Bayda terrane.