Geochemical exploration in Darreanjir Mountain (1:20000)
Reza Hosseinzadeh and Behzad Barati
The area of studied region is 27 km2. It is located at 1:25000 topography maps of Darreanjir Mountain I and III that belongs to 1:100000 sheet of Abriz in Ardakan Quadrangle. The area is bounded between 55?5'00" to 55?8'00" eastern longitudes and 32?23'45" to 32?27'00" northern latitudes in Yazd province (130 km northeast of Yazd), between Saghand and Kharangh villages.
This area is part of central Iran. Posht-e Badam is the most important fault in the area. Regional lithology includes gneiss, migmatite, amphibolites, anatexite and some schist and marble of Precambrian Chapedouni complex, Precambrian- lower Cambrian carbonate clastics, sedimentary and volcanic rocks, Tertiary volcanics and Quaternary deposits. The age of dioritic and granodioritic intrusives is Triassic and sometimes middle Eocene. The contact of Chapedouni complex with a granite (g3) body forms the main mineralized zone.
Previous surveys (1:100000 of Abriz) marked significant anomaly of Mo and W with weak anomaly of Au, Y, Sb, Cd and Pb elements in the area. Heavy mineral sampling yielded high amounts of scheelite with tourmaline, pyrite oxide, orpiment, apatite, epidot, zircon, smithsonite, fluorite and malachite.
129 stream sediment samples, 37 heavy mineral samples and 99 rock chip and mineralized samples were analyzed for these elements: Sb, Ba, Bi, As, Hg, Ag, Cu, Zn, B, Be, Pb, Sn, Mo, W, Au, Cr, Co, Ni, Ti and Mn. W and Mo were analyzed by polarography method and the other elements by spectrography.
By doing required statistical analysis, four anomalous zones were identified.
1- Number 1: it is main mineralized zone that located in southeast of Darreanjir Mountain exploration area, 3.5 km2 wide. Cu, Mo, Sn and W are anomalous in this zone, although Zn, Pb and Ag are relatively anomalous. Mo mineralization in concentrated in silicic veins. W, Sn and Ag mineralizations occurred in three phases that include silicic veins in metamorphic and granite rocks, calcite veins in metamorphic rocks, hornfelses and skarns in the contact of intrusive rocks with metamorphic complex.
2- Number 2: at center of exploration area, W and Mo mineralizations have occurred in silicic veins in granite.
3- Number 3: it is located in northeast of exploration area. Mo, Pb and Zn elements have significant potential.
4- Number 4: it is located at east of exploration area. Zn and Cu elements have significant potential.