[S-EM12] Electric, magnetic and electromagnetic survey technologies and scientific achievements

[SEM12-12] Geophysical Investigation of Fujairah Basin, East Coast of United Arab Emirates: Insights into Tectonic Evolution

★Invited Papers

*Mohammed Ali¹、M. Ismaiel¹、M. Geng²、Ahmed Abdelmaksoud¹、S. Pilia³、A. B. Watts⁴、M. P. Searle⁴ (1.Department of Earth Sciences, Khalifa University、2.Technology Innovation Institute, United Arab Emirates、3.Department of Geosciences, King Fahd University of Petroleum and Minerals、4.Department of Earth Sciences, University of Oxford)

キーワード：Gulf of Oman, Semail ophiolite, Gravity and magnetic anomaly, Seismic reflection profile, Subsidence history

Offshore sedimentary basins to the east of the Oman-United Arab Emirates mountains developed following obduction of the Semail ophiolite and Neo-Tethyan oceanic sediments onto the previously rifted Arabian continental margin. The Fujairah basin in the Gulf of Oman underwent a complex tectonic evolution from Late Cretaceous ophiolite obduction to Oligocene-Miocene Zagros continental collision. This study uses a combination of multichannel seismic reflection profiles, gravity, and magnetic data, and well data to investigate the tectonic evolution of the basin as well as the extent of the Semail ophiolite in the Gulf of Oman, along with the post-obduction history of the Fujairah basin. The Gulf of Oman's ophiolite complex is characterized by high-amplitude Bouguer gravity anomalies and significant, short-wavelength magnetic anomalies. The top of the basement, as derived from gravity and magnetic data inversions, exhibits a depth ranging from 0 to 16 km, with a predominant north-south orientation along the coast. Analysis of seismic reflection profile data in conjunction with well data reveals thick sedimentary sequences underlying the shallow shelf (depth: 0 ? 300m) of the Gulf of Oman margin. These include a Maastrichtian (latest Cretaceous) post-obduction sequence corresponding to the Thaqab Formation, Al Khawd Formation (Paleocene), Ruwaydah Formation (Eocene), Lower Fujairah Group (Oligocene), Middle Fujairah (Miocene) and Upper Fujairah Group (Pliocene-Holocene). Interpretation of the seismic reflection profile data reveals the presence of normal faults within the Neogene and Quaternary sequences, while reverse faults are primarily confined to the Oligocene to Upper Cretaceous sequences. Analysis of fault populations indicates that reverse faults oriented in the NW-SE direction exhibit dominant dips ranging from 40° to 80°, while normal faults oriented approximately in the N-S direction display dominant dips of 40° to 65°. Backstripping analysis of biostratigraphic data in wells reflects a mid-Eocene comp
ressional deformation due to the Arabian plate ? central Iran plate collision (Zagros orogeny) and Miocene extensional events probably related to the culmination and uplift of the Musandam peninsula and/or the flexure of the lithosphere as a result of the Arabian Plate subduction beneath the Makran trench.