This article was accepted into the corpus but its outbound wikilinks were never NER-processed — typical at the deepest BFS hop or when the run's entity cap was reached. No expansion funnel to show.
| Oman ophiolite | |
|---|---|
| Name | Oman ophiolite |
| Other name | Semail Ophiolite |
| Location | Muscat, Al Batinah Region, Dhofar Governorate, Oman |
| Coordinates | 23°N 58°E |
| Type | Ophiolite complex |
| Area | ~50,000 km² |
| Primary lithology | Peridotite, gabbro, sheeted dikes, pillow basalt |
| Named for | Semail |
| Region | Hajar Mountains |
Oman ophiolite The Oman ophiolite is the world's most complete and best-exposed ophiolite complex, renowned for its intact mantle sequence, crustal sections, and mafic volcanics. It spans much of northeastern Oman and parts of the United Arab Emirates and is central to studies that link field observations to models of mid-ocean ridge processes, forearc dynamics, and plate boundary evolution. The complex has attracted multidisciplinary work from institutions such as the US Geological Survey, University of Oxford, Imperial College London, and the Sultan Qaboos University.
The ophiolite crops out along the Hajar Mountains and includes peridotite massif, layered gabbro, sheeted dike complex, pillow lava, radiolarian chert, and sedimentary cover linked to the Tethys Ocean and Arabian Plate evolution. Field campaigns by teams from Smithsonian Institution, Caltech, ETH Zurich, Université Paris-Sud, and National University of Singapore have documented structural, geochemical, and petrological details that inform models developed by researchers at Lamont–Doherty Earth Observatory, Scripps Institution of Oceanography, and Woods Hole Oceanographic Institution.
The ophiolite sits atop the autochthonous Arabian continental margin adjacent to Musandam Peninsula and overlies sequences correlated with the Nafud Basin and Huquf Depression. Emplacement models invoke obduction during convergence between the Arabian Plate and Eurasian Plate, influenced by closure of parts of the Neotethys Ocean and collision events associated with the Zagros Orogeny, Makran Accretionary Prism, and rifting linked to the Red Sea. Structural analyses reference thrusting, large-scale fold geometries, and transport linked to the Makran Trench and paleo-subduction inferred from regional seismic profiles by groups including International Seismological Centre collaborators.
The stratigraphy comprises, from base to top, subcontinental mantle peridotites, upwards into layered and isotropic gabbros, sheeted dike complexes, pillow basalts, and pelagic sediments including radiolarite and limestone. Peridotite bodies such as the Wadi Tayin Massif exhibit harzburgite, dunite, and olivine clinopyroxenite assemblages comparable to mantle sections sampled at the Kerguelen Plateau and Mid-Atlantic Ridge dredge sites. The sheeted dike complex correlates with exposures near Muscat and parallels structures documented at Troodos Ophiolite and Kurile Islands ophiolites. Overlying sedimentary successions include radiolarian cherts similar to sequences in the Alboran Sea.
Geochemical signatures include depleted mantle peridotite compositions, enriched mid-ocean ridge basalt (E-MORB) to normal MORB (N-MORB) transition in gabbros and basalts, and subduction-influenced trace element patterns in alteration zones. Isotopic studies using Sr-Nd-Pb systems by teams at Max Planck Institute for Chemistry, University of Tokyo, MIT, and Stanford University show heterogeneity consistent with mantle melting beneath spreading centers and metasomatism related to slab-derived fluids comparable to observations from the Mariana Arc. Mineralogical studies highlight olivine, orthopyroxene, clinopyroxene, spinel, and amphibole textures documented with electron microprobe work at Lawrence Berkeley National Laboratory and Argonne National Laboratory.
Radiometric ages from U-Pb zircon, Ar-Ar on amphiboles, and Sm-Nd model ages constrain oceanic crust formation and obduction to Late Cretaceous to early Paleogene intervals, contemporaneous with tectonic events that affected the Iberian Peninsula and Anatolia. Plate reconstructions incorporating data from Paleomap Project, paleomagnetic results from Geological Survey of Japan, and thermochronology from the British Geological Survey suggest formation at a spreading ridge and subsequent obduction during convergence involving the Gondwana breakup remnants, closure of Neotethys, and emplacement linked to the Laramide Orogeny-equivalent stresses in the Arabian margin.
The ophiolite hosts significant chromitite, platinum-group element (PGE), nickel, cobalt, and copper mineralization, making it a target for economic geology investigations by the Oman Ministry of Oil and Gas, Shell Oil Company, BP, and junior exploration firms. Chromium deposits occur in podiform chromitites analogous to those mined in South Africa and Siberia; serpentinized peridotites are evaluated for chrysotile and magnetite occurrences with geotechnical studies by Rio Tinto Group and BHP. Hydrothermal alteration zones have been studied for volcanogenic massive sulfide (VMS) analogs by researchers associated with Norwegian University of Science and Technology and Canadian Geological Survey.
Early descriptions by Gustafson (20th century) and mapping by the British Museum (Natural History) set the stage for systematic work in the 1950s–1970s led by teams from UCL, University of Cambridge, and Imperial College London. Seminal contributions include tectonic syntheses by John Dewey, petrological models by Hugh Green, geochemical compilations by Ian Graham, and isotope chronologies by Ken Kelley. Modern advances have come from integrated drilling in collaboration with the International Ocean Discovery Program, remote sensing by European Space Agency, and numerical modeling at Princeton University and ETH Zurich. Ongoing research continues at institutions such as King Abdulaziz University and University of Bristol.
Category:Geology of Oman Category:Ophiolites