The Jebel Thurwah upper Proterozoic ophiolite complex, western Saudi Arabia

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doi: 10.1144/gsjgs.141.3.0537
Authors:Nassief, M. O.; Macdonald, R.; Gass, I. G.
Author Affiliations:Primary:
King Abdelaziz Univ., Jedda, Saudi Arabia
Univ. Lancaster, Dep. Environ. Sci., United Kingdom
Open Univ., Dep. Earth Sci., United Kingdom
Volume Title:Journal of the Geological Society of London
Source:Journal of the Geological Society of London, Vol.141(Part 3), p.537-546. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0016-7649
Publication Date:1984
Note:In English. 35 refs.; illus. incl. 2 tables, geol. sketch maps
Summary:The mafic-ultramafic igneous complex occupying some 40 km2 in west-central Saudi Arabia was tectonically dismembered and emplaced as thrust slices into an island-arc volcano-sedimentary sequence >680 m.y. ago. It contains tectonized harzburgite with dunitic lenses, layered mafic and ultramafic plutonic rocks, as well as gabbros, tonalites and plagiogranites, and also sheeted dykes and pillow lavas. Major-oxide and trace-element analyses suggest that the complex was originally oceanic lithosphere formed above a subduction zone. During a subsequent collison, this ophiolite was thrust onto an Upper Proterozoic island-arc sequence of andesitic-rhyodacitic rocks of tholeiitic transitional to calc-alkaline affinity. This mass lies in a NE-SW zone of ophiolite complexes extending from Bir Umq (150 km to the NE) to NE Sudan that marks a suture between island-arc systems subsequently accreted to form the continental crust of the Arabian-Nubian Shield. [R.A.H.]
Subjects:Andesites; Basalts; Calc-alkalic composition; Complexes; Continental crust; Crust; Dikes; Diorites; Dunite; Gabbros; Geochemistry; Granites; Harzburgite; Igneous rocks; Intrusions; Island arcs; Lava; Mafic composition; Ophiolite; Peridotites; Petrology; Pillow lava; Plagiogranite; Plutonic rocks; Rhyolites; Subduction; Tholeiite; Tonalite; Trace elements; Ultramafics; Volcanic rocks; Africa; Arabian Peninsula; Arabian Shield; Asia; East Africa; Nubian Shield; Saudi Arabia; Sudan; Bir Umq; Jebel Thurwah Ophiolite; Khor Nakasib; Sarian Series; Thurwah; Wadi Amur; Western Saudi Arabia
Coordinates:N224000 N224800 E0393000 E0392000
Abstract Numbers:84M/3372
Record ID:1985081103
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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