mohammad parchekani; M Shahrabi; K Bazargani-Guilani
Abstract
The west Alborz area with a crustal thickness of 35-40 Km is a part of the Alborz ranges and is located in the western part of the Alpine-Himalaya belt. This area is folded by Alpine orogeny and the orogen is formed by collision between Iranian and Arabian blocks. A thick and widespread sequence of volcanic ...
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The west Alborz area with a crustal thickness of 35-40 Km is a part of the Alborz ranges and is located in the western part of the Alpine-Himalaya belt. This area is folded by Alpine orogeny and the orogen is formed by collision between Iranian and Arabian blocks. A thick and widespread sequence of volcanic and pyroclastic rocks with 3800m thickness, Eocene in age, outcropped in west Alborz (Karaj Formation, KF). These rocks are intruded by younger plutons with Tertiary age. There are numerous geological, petrological, stratigraphical, geochemical and tectonical similarities between Miocene volcanic rocks in Turkey and study area in Iran (Eocene). The only difference is in age of volcanism in Turkey and Iran.
K. Bazargani-Guilani; M. Parchekani
Abstract
Barik-Ab Pb-Zn (Cu) ore deposit located in 2 km for front Barik-Ab village in north of Abhar town, south eastern of Zanjan province. According to the geological classification of Iran , this area located in Taroum mountains and is a part of west Alborz range , Alborz-Azarbaidjan zone or west of central ...
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Barik-Ab Pb-Zn (Cu) ore deposit located in 2 km for front Barik-Ab village in north of Abhar town, south eastern of Zanjan province. According to the geological classification of Iran , this area located in Taroum mountains and is a part of west Alborz range , Alborz-Azarbaidjan zone or west of central Alborz with the trend of NW – SE, located in Upper Cretaceous magmatic belt. In the Taroum Mountains, the main outcrops are volcanic and pyroclastic rocks which this sequence is comparable with Karaj Formation and divided into two members. The lower member is called Kordkand (2400 m) and the Upper member named Amand (1400 m).Amand member is divided to 6 submembers. Submembers are Ea1, Ea2, Ea3, Ea4, Ea5, and Ea6. Outcrops in the studied Area are Ea4, Ea5 and Ea6. Barik-Ab ore deposit occurred in Ea4 which is included andesite, rhyolite, breccia tuff, tuff and sandstone and tuffacouse mudstone rocks. Host rocks are rhyolitic, dacitic and rhyodacitic tuffs. Mineralization in Barik-Ab Pb-Zn(Cu( ore deposit divided in two stages: in the first stage mineralized hypogen ore minerals including sphalerite, galena, chalcopyrite, pyrite, bornite and, in second stage formed covelite , malachite , azurite hematite, goethite and limonite by enrichment processes. According to the increase of Cd and decrease of Zn/Cd in the sphalerite and galena and up value of Ag and Sb and decrease of Se/S*10-4 in the galena and the correlate with other Pb-Zn mineralization types, Barik-Ab Pb-Zn(Cu) ore deposit formed by influence of medium temperature? Hydrothermal fluids into tuff host rocks after the Eocene and mineralization occurred with veinlets and vein formed in the joints, fracture and faults with Silicification alteration in host rock.
