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Fatemeh Sabahi, Geological survey of Iran (Islamic Republic of Iran)
Mahmmod Mehrpartou, Geological survey of Iran (Islamic Republic of Iran)
Alireza Babakhani, Private company (Islamic Republic of Iran)
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The Alborz mountain range, forming an EW active folded-thrust belt across northern Iran,constitute a part of the andesitic volcano-polotonic Alpine- Himalayan orogeny in western Asia.The studied region displaying a complete stratigraphic sequences of the late Precambrian (kahar F.M) to the Pliocene in age. Paleozoic composed of widesparead dolomite, marl and shale sediments that were deposited in a shallow and shelf-depth, in Central Alborz. Permian considers as an important time for lead and zinc mineralization. In Permian stratigraphic sequence, there are numerous deposits as well as Duna deposit in middle Permian (Ruteh F.M).The most aboundant paragenetic minerals in the Permian lead and zinc deposits in Central Alborz; are sphalerite and galena, barite,flurite,calcite and dolomite.Quartz and pyrite are common gangue minerals and in some deposits copper mineralization is present.
In Triassic development of the teyhys ocean is significant, limestone and dolomite are major sedimentary rocks. Puchi-miana deposit, take into account as important F-Ba-Pb mineralization in middle Teriass(Elika F.M.).
Jurrasic sequence composed of alternative sandstone, shale with obvious fauna and siltstone (shemshak Formation).Sporadic volcanism occurs during the deposit of the molassic Shemshak F.M. with continuation carbonatic rocks of Dalichay and Lar F.M. In Lar Formation,Namar deposit considers as important Pb-Zn mineralization which has been occurred as vein and karstic cavities filling within that related to subvolcanic intrusives.At the base of data, presence of calcsilicate minerals and obvious mineralization haloes represent skarn type mineralization in this area.
In Central Alborz, marrin sequences deposited during the cretaceous age. The Cenozoic is known by the Alpine orogenic movements which accompanied by the precipitation of flych-like sediment and volcano-sedimentary unites which deposited in Eocene time. During the Miocene and the Pliocence, molassic sediments were deposited.There are many vein deposits that intruded in Eocene volcano-sedmentary unites as well as Zehabad,Lak,Ipak.
As a result temporal and spatial investigation in Pb-Zn mineralization in Central Alborz, there are 3 types of Pb-Zn mineralization in Central Alborz, 1)stratiform-stratabound deposit, (2)vein deposit and (3)skarn type.
At the base of; geological data and geochemistry,lithology,stratigraphy and tectonic studies and all evidence for temporal and spatial mineralization in Central Alborz;majority of Pb-Zn mineralization have been occurred in Permian to Triassic period,metalogenic characteristics of these deposits indicate that they are comparable with the MVT type deposits, while in Tertiary pb-zn mineralization displaying vein-type deposits which genetically are connected with hydrothermal phases of post Eocene volcano-polotonic activities.
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