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oa Petrography and petrology of Rebat Intrusion, southern Sanandaj-Sirjan Zone, Iran
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, GEO 2008, Jan 2008, cp-246-00281
Abstract
A number of mafic-ultramafic intrusive bodies of Late Triassic-Jurassic age are exposed 30 kilometers to the south of Rebat village (east of Hearat city, Yazd Province) and southwest of Shahrebabak city (Kerman Province) in Iran, These bodies have a variable lithology consisting of wherlite, olivine-pyroxenite, serpentinized dunite, anorthosite, olivine-gabbro, gabbro, monzo-gabbro, quartz-bearing monzo-gabbro to quartz monzonite. The results of geochemical studies indicate a cumulative character for both mafic and ultramafic rocks for these intrusions. The mafic rocks seem to have originated from magmas with low-silica alkaline elements (including titanium) and high calcium and magnesium content. Differentiation and contamination of the magma at the final stages of crystallization gave rise to a wide range of intermediate rocks. The assessment of the (La/Yb) N ratio points towards the formation of mafic-ultramafic rocks from mantle material that were highly depleted, signifying that their parent rocks were poor in garnet.<br>The magmatic series of the mafic rocks fall within alkaline compositions, whereas the differentiated ones belong to sub-alkaline varieties. Comparison of mafic-ultramafics with normalized patterns of primary mantle indicates that they formed due to extensive partial melting of mantle rocks. The tectono-magmatic environment of the mafic rocks falls in the realms equivalent to alkaline basalts of intra-cratonic rifts, whereas that of the differentiated rocks have affinities with continental basalts.