the study area is located at northwest of sarbisheh in south khorasan province and eastern border of lut block. in this area, tertiary (eocene-oligocene to pliocene) volcanic rocks consisting of basaltic andesite, dacite, rhyodacite, vitreous rhyolite (perlitic in some parts), tuff and ignimbrite are exposed. in the daghar mountain, a, b and c perlite layers with thicknesses of 102, 7 and 58 me...