The petrography and mineral chemistry of the volcanic rocks associated with salt domes (Northeast of Ardakan, Yazd province)

The Kalut area is located at about 70 km northeast of Ardakan (Yazd), which is a part of the structural zone of Central Iran (Yazd block). The igneous rocks of the area belong to Tertiary and are subdivided into intermediate (microdiorite) and basic rocks (basalt and microgabbro). The majority of these rocks show intergranular textures. Plagioclase (albite to bytownite), clinopyroxene (diopside) and olivine are the main minerals of basic rocks. Mica (biotite), apatite and Fe-Ti oxides are accessory minerals. Albite, calcite, chlorite, epidote, amphibole, opaque, sphene, prehnite formed during alteration process. The main textures of intermediate rocks are intergranular. Plagioclase (oligoclase to labradorite), amphibole and clinopyroxene (diopside) are the significant minerals of the aforementioned rocks. The chemistry of clinopyroxenes and the existence of pillows in exotic magmas of mafic rocks, imply that during formation of magma it was mixed with another basic magma, which the nature and the sources of these magmas were likely similar. The results of petrogenetic studies by using mineral-chemistry of clinopyroxene indicate that the composition of magma is tholeiitic to calc-alkali basalts which is related to volcanic arc zone.