Petrography and geochemistry of rhyolite rocks in the Se- Chahun iron oxide deposite, Bafq mining district, Central Iran

Bafq metallogenic province is located in central Iran about 115 Km Southeast of the Yazd city. This metallogenic province is a narrow paleorift extending northward from south of Bafq to Robat- Posht– Badam and suggested age of 750 – 540 Ma for it. There is an alkaline - calc-alkaline bimodal composition at these environments. Contrary, alkaline-sub alkaline bimodal suites occur in anorogenic continental rift settings. The Se–Chahun Iron Ore mine is containing two major groups of ore bodies called the X and XI anomalies. Volcanic rocks are rhyolite and rhyodacite in composition and the sedimentary rocks are mainly dolomite. These ore bodies are commonly associated with pervasively altered rhyolitic tuffs and sandstones. One of the important volcanic rocks in the study area is rhyolite rocks and are host rocks for Iron mineralization These rocks have a Porphyry texture with micro granular mesostasis. phenocrysts of this rock are quartz and plagioclase. Quartzs are anhedral to subhedral shapes and plagioclases are albite to oligoclase. The properties of these minerals can be mention to albitepericline and albite-carlsbad twinning. These minerals developed to clay mineral, sericite, chlorite and calcite. Rhyolite mesostasis are containing fine grain quartz and microlitic plagioclase that developed to clay minerals. Accessory minerals in these rocks are opac mineral, calcite and chlorite. In the distinguish diagrams, rhyolite rocks are plotted in the calc-alkaline area. Chemical properties of rhyolites are approaching to I-type. Separation of tectonic environment proposed a range of within plate rocks (WPG) and within place volcanic zone for rhyolite rocks.