Survey of As element dispersal around the Abbas Abad copper deposits (East of Shahroud) with special reference to Madan Bozorg deposit

Abbas Abad area has an old copper mining history; in this area outcrop of volcanosedimentary sequences exist; lithological composition of volcanic parts are generally andesite and trachyandesite and sedimentary parts includes sandstone, limestone, conglomerate and shale. Mineralization in this area has occurred in a broad region (
35 Km2) in volcanic rocks with porphyry to megaporphyry texture. For surveying of arsenic distribution in this area chemical analysis on 52 samples of stream sediments near deposits located in north and northeast part of Abbas Abad (including Damanjala, Madan Bozorg, Asiadiv and Lab-e-Kal deposits) were done. Arsenic distribution, according to broad mineralization and old mining history were stndied. Arsenic distribution map shows the highest concentration of arsenic is in north east of the region; also using arsenic contents of stream sediments, background,threshold and anomaly values of arsenic determind which are 16 ppm, 21 ppm and 33 ppm respectively.