Geochemistry and petrogenesis of crustal sequence of Kamyaran ophiolite complex (NW Iran)

The Kamyaran ophiolites, with the age of Late Cretaceous, are a part of the Iranian Mesozoic ophiolites, which are exposed in the SW of Zagros Main Thrust. This massif is bordered at the NE by the Sanandaj-Sirjan metamorphic rocks and at the SW by the Bisotun limestones and Kermanshah radiolarites and then by the Zagros Fold-Thrust Belt. The Kamyaran ophiolite is made of the mantle and crustal sequences. The crustal sequence is distinguished by pillow lavas, sheeted dike complex, and lava flows. The positive LILE anomalies with the HFSE depleted confirm their arc-related affinity. The geochemistry signatures of sheeted dikes show that these rocks have two different patterns. The REE pattern in some of the sheeted dikes samples with the pillow and flow lavas sample is similar to E-MORB; their element ratios support this likeness too. The positive LREE and LILE anomalies with the depletions of the HFSE suggest the calc-alkalic tendency and subduction-related affinity for these rocks; however, dacitic dikes with the flat REE pattern, LILE enrichment, and HFSE depletions have the Island-arc tholeiites affinity. The similarity of element ratios in all the samples may suggest that these rocks have the same magma source, and the tectonic environment of the ophiolitic rocks can be correlated with the oceanic subduction environment.