Document Type : Original Research Paper

Authors

1 Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran Faculty of Earth Sciences, Damghan University, Damghan, Iran

2 Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran

3 Ecole et Observatoire des Sciences de la Terre, Universite de Louis Pasteur, Strasbourg, France

Abstract

Basalts, gabbros, tuffs, diabasic dikes, agglomerates and breccias and the rock fragments of breccias are the main mafic constituents of the Balvard-Baft ophiolites. Geochemical signatures of these rocks reveal depletion in HFSE and enrichment in LILE and simultaneous occurrence of island-arc tholeiitic and calc-alkalic volcanisms. These geochemical behaviors are the evidences suggesting that these mafic rocks are of supra-subduction zone affinity. These special signatures associated with the position of the Nain-Baft ophiolitic belt behind the Mesozoic magmatic arc of the Sanandaj-Sirjan zone, suggest back-arc spreading (in the active margin of the Central Iranian block), during middle Cretaceous due to the oblique subduction of Neo-Tethys beneath the Central Iranian block.

Keywords

References
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