Study of mineralization and origin of Pliocene conglomerate hosted strata bound sedimentary Cu mineralization in the Ghareh-Aghaj, Maku

The study area is located in the Northwest of Iran and North of Khoy Ophiolite Belt. Rocks of the Ghareh-Aghaj region include Qum formation, Upper Red Formation and Pliocene conglomerate. Pliocene rock units consist of siltstone, sandstone (arkose and lithic arenite) and microconglomerate- conglomerate. Pliocene cicroconglomerate- conglomerate hosted strata bound copper mineralization in the Ghareh Aghaj region, but the mineralization is partially seen in the sandstone unit. Much of the mineralization in the study area is open space filling and disseminated. Ore mineralogy of Ghareh-Aghaj is very simple and contains of native copper, cuprite and tenorite. Lack of copper sulfides, the absence of plant fossils as reducing agent, and the non-occurrence of copper replacement instead of plant tissues, occurance of mineralization as the open space filling and cement grain and formation of native copper as the main ore, all represent the dissimilarity of Ghareh-Aghaj Cu mineralization with Redbed type sedimentary copper deposits. Formation of Ghareh-Aghaj copper deposit can be explained as follows: Pore water formation of diagenetic processes within the Upper Red Formation caused the leaching of copper from this sequence and the formation of copper chloride complexes. Increasing of water table caused the development of reducing conditions in the Pliocene conglomerate. Therefore entrance of Copper-bearing fluids caused native copper deposition below the water table. Decreasing of groundwater table and exposure of native copper to the oxidizing conditions caused the replacement of cuprite, malachite and azurite with native copper.