Investigating the petrology and economic geology of manganese mineralization traces in Khorasanak, south of Hashtrood
The studied area is located in the south of Hashtrood, which is a part of Orumieh— Dokhtar volcanic belt. The volcanic rocks are mainly andesite. Chemical analyses show that they arc calc— alkaline and have potasic and peralumineous nature. The depth of’ original magma was between 20 —30 km. The volcanic rocks are
covered by gypsiferrous marl and limestone. Manganese oxides have occured as hands and lamineas interhedded with these marl.
The thickness of these hands varries between 1 and 20 cm. Thesc are precipitated from hydrothermal fluids derhved from volcanic activities. These deposits are stratahound and syngenetic with Their hosted sediments. Because of the ahsencs of ophiolitic terrains in the studied area, this deposit is considered to he related with volcanic rocks and unrelated with ophiolitic terrains