Geochemical exploration of 1:100000 sheet of Farmahin
This area is located Markazi province, between 49.30 to 50 eastern longitudes and 34.30 to 35 northern latitudes. The region is situated in Central Iran structural zone and Uroumiyeh-Dokhtar volcanic subzone, but the southwestern corner is in Sanandaj-Sirjan zone. Important faults of the area include Talkhab, Zaghar, Ezzedin, Farasmaneh, Zorgin and Tafresh reverse faults.
Exposed rock units involve Triassic Noqrekamar limestone, limestone, shale, and sandstone of Triassic, Jurassic shales, limestone of Cretaceous, sedimentary-volcanic complex of Eocene, conglomerate and marlstone of Oligocene, Qom formation of Oligocene, Miocene Upper Red Formation, Pliocene and Quaternary alluvium and conglomerates. Composition of igneous bodies ranges between intermediate to basic.
In the project, prepared stream sediment samples were analyzed for 22 elements (Mo, Ni, Pb, Sn, Sb, Sr, Ti, Ag, As, Au, Bi, B, Co, Cu, Cr, Cd, Fe, Hg, Mn, V, W and Zn). After analysis, statistical analyses of raw data, rock classification, assessment of Clark values in exposed rocks, calculation of enrichment index, statistical parameters calculation of enriching index, correlation coefficients, multi-variable statistical processes, cluster analysis, and network estimation were done.
In anomalies control phase 142 heavy mineral samples studied. The heavy minerals were classified by cluster analysis. The identified groups include:
Group 1: goethite, corundum, pyrite oxide, mimetite, galena, pyromorphite, pyrolusite, apatite and cerussite
Group 2: malachite, chalcopyrite, barite and zirconium
Group 3: routile, pyrite, orpiment and anatase
Group 4: hematite, oligiste, magnetite and native copper, sphene, cinnabar and native lead
Finally 59 mineralized samples taken from the anomalous zones contain kaolinite, pyrite, hematite, limonite, gold, malachite, azurite, chalcopyrite, magnetite, galena, bornite and barite.
With compilation of anomalies data, eight potentially important mineralized zones are as following:
1- South of Farasmaneh village in 1:50000 sheet of Bazarjan
2- West and southwest of Farak in 1:50000 sheet of Bazarjan
3- South of Joftan village in 1:50000 sheet of Bazarjan
4- South of upper Tararan village and surroundings of Zaghar village in 1:50000 sheet of Shahrab
5- Northeast of Talkhab village in 1:50000 sheet of Farmahin
6- Surroundings of Kasreasef village in 1:50000 sheet of Khanjin
7- Northwest of Tarizabad village in 1:50000 sheet of Khanjin
8- Barite mine area of Soltanabad in 1:50000 sheet of Khanjin, east of Koureh village
Based on ore deposit modeling, four anomalies are first priorities:
Anomaly 1- South of Farasmaneh, in 1:50000 sheet of Bazarjan, correlated models include layered barite, sandstone-hosted Pb-Zn, skarn Pb-Zn, exhalative sedimentary Pb-Zn.
Anomaly 4- correlated models include Sado type Au, low angle shear zones, Au-U-Cu Olympic dome, and Comstock Au.
Anomaly 6- the models include layered-barite, sandstone-hosted Pb-Zn.
Anomaly 7- correlated models include Besshi massive sulfide, layered barite, Kuroko massive sulfide, Creed vein Au, and Au-U-Cu Olympic dome