Geochemical exploration in 1:100000 sheet of Aran
The study area includes parts of Isfahan and Tehran provinces. This sheet is bounded between 51? to 51 ? 30' eastern longitudes and 34? to 34?30' northern latitudes. Western section of the sheet is mountainous. Its rocks involve Tertiary volcanic rocks and limestones of Qom formation. Qom Namak Lake (playa) is dominant feature of eastern section of the sheet. Cropping out rock units in the region include andesite, basalt, tuff and clastic rocks of middle-late Eocene, felsic to basic volcanic rocks, limestone and clastic deposits of late Eocene, sandy and limy marl, sandstone, siltstone, and claystone with conglomerate intercalations of Eocene-Oligocene, clayey shale, gypsiferous marl, sandstone, limestone and salt with basic dykes of Oligocene, Oligocene Qom formation, andesitic to dacitic lavas of Miocene, Pliocene to Quaternary conglomerate, sandstone and claystone. From structural view, there are three main fault zone including Shourab, Barikarasf and Aran-Bidgol. Dominant trend of faults is NW-SE. The region has good known mineral potential. For example Gheh is a iron mine with magnetite and hematite mineralization, Nigh at northwest of Nigh farm with chalcopyrite, pyrite and galena mineralization, magnetite and hematite mineralization in south and southwest of Kermeh and also 2.5 Km southeast of Kermeh and Veshnaveh lead mine.
In this project, 562 geochemical samples were sent to Australia to be analyzed for 44 elements. After classifying into four rock classes, required statistical analyses were applied on the data. Censored data processing, cluster analysis, network estimation, enrichment index calculation, uni- and multivariables analysis are examples of these analyses. As the result, preliminary map of anomalies, factor score distribution map, enrichment index maps and occurrence probability maps were produced. The controlling phase conducted by heavy mineral sampling. After modeling the data six anomalies were identified.
Anomaly number two is located at west of the region, near the lower Yahya-Abad village. Its model correlates with epithermal vein-type of Comstock, Creed type of epithermal veins, sado type epithermal veins, copper skarn and finally Almadan Hg ore deposit.
Anomaly number three located at southwest of 1:50000 sheet of Hossein-Abad-e Mishmast, northwest of Aftabru Mountain. The corresponding models to this anomalies include Sado type epithermal veins, quartz-alunite epithermal gold, Comstock, hot spring gold-silver and finally volcanic-hosted Cu-As-Sb.
Anomaly number four located in eastern portion of 1:50000 sheet of Hossein-Abad-e Mishmast, northwest of Anarboneh Mountain. Corresponding models include Sado type epithermal veins, Comstock, hot spring silver-gold, Besshi-type massive sulfide and finally volcanic-hosted Cu-As-Sb.