Geophysical Investigations of the Fujairah Basin, East Coast of United Arab Emirates: Insights Into Tectonic Evolution

Abstract

The Fujairah basin in the Gulf of Oman experienced a complex tectonic evolution related to Late Cretaceous ophiolite obduction and Oligocene-Miocene Zagros continental collision. The structure of the foreland basin in Oman-UAE is well-known, but the structure and evolution of the hinterland basin behind the obducted ophiolite and underlying thrust sheets are less understood. Therefore, we use a combination of seismic reflection interpretation, gravity and magnetic forward modeling, and backstripping of well data to investigate the spatio-temporal deformation pattern in the basin and its connection with regional tectonics operating at the Central Iran/Arabia Plate boundary. The ophiolite complex in the Gulf of Oman is characterized by high-amplitude Bouguer gravity anomalies (>120 mGal) and short-wavelength (∼10 km) magnetic anomalies with a predominant north-south orientation along the coast. The top of the ophiolite/Cretaceous oceanic crust ranges in depth from 1 to 10 km, and up to 9 km of Upper Cretaceous-Holocene sedimentary successions underlies the shelf of the Gulf of Oman margin. Normal faults are interpreted within the Neogene and Quaternary, while reverse faults are confined to the lower Miocene to Upper Cretaceous. NW-SE to NNW-SSE-oriented reverse faults exhibit dominant dips ranging from 40° to 80°, while normal faults oriented mainly in the N-S direction display dominant dips of 40°–65°. Seismic and backstripping analysis of biostratigraphic data in wells reflects an Oligocene-early Miocene compressional event due to the collision of the Arabian and Central Iran plates and late Miocene-Holocene extensional event. Onshore in the Musandam Peninsula, west-vergent thrusts such as the Hagab thrust were active synchronously with N-S-oriented normal faults along the east coast of Musandam. A more recent extensional event is linked to transtensional movement resulting from the varying convergence rates along the Minab-Zendan strike-slip fault.