Mineralogy, geochemistry, and origin of felsic dike swarms in Aqaba complex (Wadi Al-Yutum), South Jordan
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ORIGINAL PAPER
Mineralogy, geochemistry, and origin of felsic dike swarms in Aqaba complex (Wadi Al-Yutum), South Jordan Hassan Al-Fugha & Tayel El-Hasan & Ahmad Al-Malabeh & Arwa Hamaideh & Ahmad El-Mezayen
Received: 12 June 2012 / Accepted: 8 August 2012 # Saudi Society for Geosciences 2012
Abstract The present work deals with the geologic setting and mineralogical and geochemical study of Late Precambrian magmatic rocks especially the felsic dike swarms of northeast Aqaba complex in South Jordan. The northeast Aqaba complex represents one of the most significant regions in the South Jordan basement. The basement rocks in the studied region are composed of schists, gneisses, migmatites, met gabbros, diorite, and granite. It is invaded by post-orogenic dike swarms. The post-orogenic dike swarms have been recognized as felsic dikes of dacite, rhyodacite, and rhyolite composition. They are composed of plagioclase, K-feldspar, quartz, biotite, and hornblenble with a porphyritic texture. Chemically, they are enriched in compatible elements especially in the large ion lithophile elements
such as K, Rb, and Ba. The values of A/NK are more than A/CNK, indicating that dacitic dike swarms have metaluminous nature. Meanwhile, the values of A/NK are less than A/CNK in rhyodacitic and rhyolitic dike swarms of prealuminous nature. This felsic dike can be related to an intercontinental setting that was accompanied by a chemical evolution of the extensional movements and is formed by partial melting of crustal rocks, which are already known from other areas in the northeast portion of the Arabian-Nubian Shield. Keywords Felsic dikes . Aqaba complex . Partial melting . Post-orogenic . Jordan . Arabian-Nubian Shield
Introduction H. Al-Fugha Department of Geology, Jordan University, Amman, Jordan e-mail: [email protected] T. El-Hasan Department of Geology, Faculty of Science, Taibah University, 344, Al-Madinah Al-Munawarah, Kingdom of Saudi Arabia e-mail: [email protected] A. Al-Malabeh (*) Department of Earth and Environmental Sciences, Hashemite University, P.O. Box 150459, Zarka 13115, Jordan e-mail: [email protected] A. Hamaideh WERSC, University of Jordan, P.O. Box 11942, Amman, Jordan e-mail: [email protected] A. El-Mezayen Geology Department, Faculty of Science, Al-Azhar University, Cairo, Egypt e-mail: [email protected]
The Precambrian basement complex of Southern Jordan forms the northern part of the Arabian-Nubian Shield. The study area deals with the felsic dike swarms and their relationships with the Late Precambrian granite. The study area is dominantly composed of Precambrian basement rocks including schists, gneisses, migmatites, metagabbros, diorite, and granite. The crusted structures of the ArabianNubian Shield resulted from complex events of subduction, accretion, and extension during Pan-African times (950– 550 Ma) after Kroner (1985). The geological evolution has been described in terms of subduction-related processes involving arcs and micro plate accretion (McCourt 1988) who dated the Aqaba basement
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