Sheykh Abad area is located in South Khorasan Province, about 90 km south-west of Birjand. The geographical coordinates of area is 59° 00¢ 50² to 59° 06¢ 20² longitude E and 32° 26¢ 20² to 32° 29¢ 32² latitude N. The study area is located in geotectonic Lut Block zone. Eocene sub-volcanic units are altered by hydrothermal solotions in Skeykh Abad area. Kaolinite, Montmorillonite and quartz are ...