Granitic and metamorphic rocks of the Taif area, western Saudi Arabia

Abstract

Research Article| December 01, 1977 Granitic and metamorphic rocks of the Taif area, western Saudi Arabia A. O. NASSEEF; A. O. NASSEEF 1Department of Geology, King Abdulaziz University, P.O. Box 1540, Jeddah, Saudi Arabia Search for other works by this author on: GSW Google Scholar I. G. GASS I. G. GASS 2Department of Earth Sciences, The Open University, Milton Keynes MK7 6AA, Great Britain Search for other works by this author on: GSW Google Scholar GSA Bulletin (1977) 88 (12): 1721–1730. https://doi.org/10.1130/0016-7606(1977)88<1721:GAMROT>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation A. O. NASSEEF, I. G. GASS; Granitic and metamorphic rocks of the Taif area, western Saudi Arabia. GSA Bulletin 1977;; 88 (12): 1721–1730. doi: https://doi.org/10.1130/0016-7606(1977)88<1721:GAMROT>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The Taif area occupies 170 km2 at the western margin of the Saudi Arabian Hijaz plateau, where granitic rocks, which form about 55% of the total outcrop, have been intruded into amphibolites and quartzo-feldspathic gneisses. The host rocks have been metamorphosed to the almandine-amphibolite facies and have petrographic and geochemical features that suggest that they were originally igneous rocks of calc-alkalic affinity. The granitic intrusions have been divided into four groups (G1, G2, G3, and G4) on the basis of field relations, chemistry, and textures; G1 through G3 are synkinematic, and G4 is postkinematic. The granitic rocks are calc-alkalic. Isotopic data suggest that they were emplaced between 595 and 525 m.y. ago; initial 87Sr/86Sr ratios (0.703 to 0.710) indicate an origin by partial fusion of the mantle or anatexis of the lower crust. Field, geochemical, and petrographic studies suggest emplacement in an island-arc environment. This is compatible with other investigations that have led to the conclusion that the crystalline basement of Arabia and northeast Africa is the product of cratonization of island arcs over a period of 600 m.y. (from 1,100 to 500 m.y. ago). The Taif granitic rocks represent final phases in the episodic cratonization process. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.