Geophysical imaging of ophiolite structure in the United Arab Emirates

• Published in: Nature communications Vol. 11; no. 1; p. 2671
• Main Authors: Ali, M. Y., Watts, A. B., Searle, M. P., Keats, B., Pilia, S., Ambrose, T.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 29.05.2020; Nature Publishing Group; Nature Portfolio
• Subjects: 704/2151/213/536; 704/2151/2809; 704/2151/562; Continental margins; Dipping; Geological faults; Geophysics; Humanities and Social Sciences; Magma; multidisciplinary; Oceanic crust; Plates (tectonics); Science; Science (multidisciplinary); Sedimentary basins; Subduction (geology); Gulf of Oman; United Arab Emirates
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-16521-0

The Oman-United Arab Emirates ophiolite has been used extensively to document the geological processes that form oceanic crust. The geometry of the ophiolite, its extension into the Gulf of Oman, and the nature of the crust that underlies it are, however, unknown. Here, we show the ophiolite forms a high velocity, high density, >15 km thick east-dipping body that during emplacement flexed down a previously rifted continental margin thereby contributing to subsidence of flanking sedimentary basins. The western limit of the ophiolite is defined onshore by the Semail thrust while the eastern limit extends several km offshore, where it is defined seismically by a ~40–45°, east-dipping, normal fault. The fault is interpreted as the southwestern margin of an incipient suture zone that separates the Arabian plate from in situ Gulf of Oman oceanic crust and mantle presently subducting northwards beneath the Eurasian plate along the Makran trench. The Semail ophiolite provides evidence for geological processes that form oceanic crust, however, its deep structure remains debated. Here, the authors use geophysical imaging to determine that the ophiolite is bound by a thrust fault in the west, and a normal fault in the east, bounding a rapidly subsiding basin, implying the ophiolite may not be rooted in the Gulf of Oman crust.