Petrogenetic interpretation of Cu hosted Eocene volcanic rocks in southwest of Ardestan, East of Isfahan

Abstract

In the present study, study areas the part of Urumieh- Dokhtar volcanic belt. The main of rocks in this area are Eocene volcanic rocks consist of lava and pyroclastic rocks, with andesite and andesite basalt composition. These rocks are the most important cu-hosting ones in thisareaand have aporphyritic texture, cavity, flow, cellular foam, glomeroporphyritic, poikilitic and spherulitic textures, and in handy specimens are generally fine grained to fine to medium grained. From mineralogical perspective, these rocks include pyroxene, plagioclase, biotite, quartz and amphibole as well as secondary minerals such as epidote, chlorite, calcite and metal ores. These rocks are not immune from alteration and in some parts of very high intensity of alteration due to hydrothermal conditions being seen. Important of alteration kinds in this area are 2 groups consist of chlorite- epidote- calcite and silicate- sericite alteration that focused at andesitic lava and generation by hydrothermal solutions. On the base of minor and trace element geochemical data on diagrams, observations of minerals, rocks and geochemistry indicate that primary magma of volcanic rocks in the area was sub-alkaline, calc-alkaline series. Also the diagrams of the tectonic characteristics show that these rocks were generated in an active continental margin volcanic arc and it is thought that are affected by the subduction. Diagrams of trace elements in volcanic rocks normalized with chondrite and primitive mantle show that enriched of the light rare earths related to heavy rare earth element probably indicates a derivation from the metasomatic mantle.