Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Ore Facies of Khanjar Pb– Ag (Zn) Carbonate– Hosted Deposit ,Upper Cretaceous Sequence in Central Iran, South Damghan, Iran

Document Type : Original Research Paper

Authors
B. Mehri 1
E. Rastad 2
F. Fayyazi 3
1 Metalic Exploration Department, Geological Survey of Iran, Tehran, Iran.
2 Economic Geology Department, Tarbiat Modarres University, Tehran,Iran
3 Geology Department, Tarbiat Moallem University,Tehran,Iran.
10.22071/gsj.2010.55420
Abstract
The Khanjar Pb– Ag (Zn) deposit is one of the stratabound deposits of Cretaceous age in Central Iran. The ore bodies may be grouped into two main geometric types: 1) Lenses of ore bodies congruent with bedding, 2) Ores as open space filling or with brecciate fabric due to faulting. Both types occur in limestone unit (k2b).Three ore bearing facies have been distinguished in the Khanjar area: 1) Siliceous limestone facies; galena, sphalerite and pyrite are the main ore minerals. Minor amounts of chalcopyrite are also visible. 2) Mullusca, Echinoderm wackstone facies with galena and sphalerite. 3) Rudist limestone facies with large amount of galena. As with other stratabound and stratiform Pb- Zn deposits, the main ore minerals are simple and few in number. In addition, galena, sphalerite and pyrite, some tetrahedrite, barite and minor amounts of copper minerals are observed. Pyrite often with framboidal texture and sphalerite with spheroidal texture form always part of paragenesis. Fluid inclusion investigations on saddle dolomite located in fractures with galena and sphalerite demonstrated the homogenization temperature of 145-230 centigrade and salinity of 17.5-23% NaCl equivalent.Geometry of ore bodies, occurrence of ore horizons in certain sedimentary facies, ore textures and structures, depositional environment (Lagoonal), paragenetic sequence of  minerals and fluid inclusion data, all suggest that Khanjar Pb- Ag(Zn) deposit is an MVT deposit.
 
Keywords
: Pb– Ag (Zn)deposit
Upper cretaceous carbonate units
Ore facies
MVT
Khanjar(Reshm)
South Damghan
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Scientific Quarterly Journal of Geosciences
Volume 19, Issue 75
Winter 2010
Pages 3-12