Geochemical Exploration in the Ahar 1:100000 sheet
The 1:100000 sheet of Ahar is located at northwest of Iran, between 47 to 47.50 degrees eastern longitudes and 38 to 38.50 northern latitudes. It contains parts of Ardebil and Azarbaijan-e Sharqi provinces.
Structurally, the region is located in the Uroomiyeh-Dokhtar magmatic belt. Based on fossils, the oldest rock units of the area are Upper Cretaceous in age. That includes andesitic to andesibasalt lavas with pyroclastic and sedimentary rocks. Extrusive igneous rocks are mostly Paleocene-Eocene in age and involve rhyolite, dacitic breccia, and some post-Eocene ignimbrites followed by red conglomerate of Neogene.
Geochemical study was conducted by analysis of 200 heavy mineral, 620 stream sediment and 28 controlling samples. These samples were analyzed in the Amdel Lab of Australia. 44 elements were analyzed of which 8 ones include censored data (Au, Hg, Ag, B, Bi, Te, Cd, Tl). Among them three elements of Te, Hg, and B were omitted because of the amount of censored data. The complete list of elements include: Au, Ag, As, B, Ba, Be, Bi, Co, Cr, Fe, Al, La, Sc, Ca, Li, P, V, Mg, K, Na, S, Zr, Th, Y, Ce, W, Zn, Pb, Hg, Mn, Ti, Cu, Mo, Ni, Sb, Sn, Sr, Cs, Nb, U, Te, Cd, Rb, Tl.
After replacing the censored data (3/4 of sensitivity limit for quantities lower than it and 4/3 of sensitivity limit for quantities higher than it), out of order data were omitted and the remained data normalized. Multi- and uni-variable statistical techniques were applied to extract required parameters. Drawing histograms, elements correlation matrix, cluster analysis, and factor analysis are of other applied techniques. As a result, six factors were identified that include:
FI = U, W, Sn (Pb)
FII = Zn, Mn, Ti, (Cu)
FIII = Ni, Cr
FIV= Au, Ag, Pb (Sb)
FV= As, Ba, Sb, Zr
FVI = Cu, Mo
Uni-element maps were prepared for 18 elements including Au, Ba, Cr, Cu, Ni, Zn, Bi, Pb, As, Mo, W, Sb, Sn, Ag, Ti, Mn, U, and Zr.
Two mineralizations have occurred in the area that includes porphyry copper mineralization of north Zargah village and alunite mineralization near the Zaylic village. Au, cinnabar, barite, scheelite, zircon, turite, ilmenite, molybdenite, and apatite are among the identified heavy minerals in the region. Copper, lead and barite were reported in 22, 18 and 2 samples respectively. Based on current study, the northern portions of the sheet and also northwest of Ahar County have potential of gold mineralization.