INTRODUCING THE MAIN AND ACCESSORY MINERALS IN THE GRANITOID BATHOLITH OF SHIRKUH, YAZD (CENTRAL IRAN) AND ITS TOURMALINE AND GARNET PHASES

Abstract

Batholith of Shirkuh, Yazd, is part of the central Iranian structural zone, located southwest of the province. The batholith is composed of five rock units, namely monzogranite, granodiorite, quartz monzonite, quartz monzodiorite, and syenogranite.The batholith, having cut through the Nayband formation (Upper Triassic), with Cretaceous limestones and a sandstone and conglomerate unit (Lower Cretaceous) lying on top as an angular unconformity, probably dates back to the Jurassic. Field and experimental investigations revealed various accessory minerals in the granite mass, including garnet, tourmaline, amphibole, zircon, sphene, apatite, biotite, muscovite, and epidote. The garnet, tourmaline, and amphibole were investigated by an Electron Microprobe (EMP), revealing the granite mass to be of almandine, grossular, and uvarovite types, the tourmaline of the rossmanite and foitite types, and amphiboles of the tschermakite and hornblende types.