Lyell Collection

This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by El-Shazly, A. K. Articles by Coleman, R. G. Search for Related Content

Metamorphism in the Oman Mountains in relation to the Semail ophiolite emplacement

Geology Department, Stanford University, Stanford, CA 94305, USA

The metamorphic rocks associated with the Semail ophiolite in the Oman Mountains represent two different facies series. Amphibolites and greenshists at the base of the Semail ophiolite constitute a metamorphic sole formed in a high-temperature, lowpressure environment. Eclogites, blueschists, lawsonite schists and other metasediments occurring at different structural levels in the basement and shelf deposits of the continental margin formed at high pressures and low temperatures. The amphibolites of the metamorphic sole formed as a result of heat transfer from the hot overthrust ophiolitic slab to the underlying oceanic sediments and volcanics shortly following intraoceanic detachment at a collapsed spreading centre about 100–90 Ma. The underlying greenschists represent sediments and volcanics that were metamorphosed farther away from the spreading centre as the ophiolitic slab became cooler and moved closer to the continental margin. Eclogites, blueschists and crossite epidote schists formed in the Saih Hatat window as a result of A-type subduction (crustal thickening) of the basement and shelf units of the Oman continental margin in response to a change in plate motion between Africa and Eurasia and transpression or collision with a fragment of Gondwanaland about 131 Ma. A-type subduction along an east-dipping zone resulted in the burial of the eastern edge of the continental margin to a minimum depth of 30 km. High P/T metamorphic rocks formed by this process followed ‘clockwise’ P-T paths. The Late Cretaceous emplacement of the ophiolite onto the continental margin of Oman resulted in the imbrication of the continental shelf deposits, the development of low-grade, high-P/T metamorphic rocks in the ‘internal’ thrust piles due to tectonic overloading and the juxtaposition of the metamorphic rocks representing different facies series. Extensional deformation associated with culmination collapse in the Late Cretaceous and Tertiary led to the exhumation of the various high P/T metamorphic rocks and the distortion of the metamorphic zones.

This article has been cited by other articles:

				D. R. Gray and R. T. Gregory Ophiolite obduction and the Samail Ophiolite: the behaviour of the underlying margin Geological Society, London, Special Publications, 2003; 218: 449 - 465. [Abstract] [PDF]

				M. P. Searle, C. J. Warren, D. J. Waters, and R. R. Parrish Subduction zone polarity in the Oman Mountains: implications for ophiolite emplacement Geological Society, London, Special Publications, 2003; 218: 467 - 480. [Abstract] [PDF]

• Home  |  
• Current volume  |  
• Table of contents  |  
• Archive  |  
• Search  |  
• Feedback

• Copyright policy  |  
• Permissions request   |  
• Terms of use   |  
• Feedback   |  
• HighWire Press