GSINET | Geological Survey of Iran , North - East Territory

Writers : Yusefi, M. A.; Razm Ara, M.; Kavoosi, N.
Refference : 28th Symposium on Geosciences and the 14th Symposium on Geological Society of Iran
Publishing Year : 1388

Abstract :

The granitoid stock at Tarik dareh, Torbat-e-Jam was investigated using RS, ICP-MS, XRF and XRD methods. In the area, Land sat Thematic Mapper (TM) data was used. The TM sensor records energy in the 0.45- 2.35 regions of the electromagnetic spectrum in 7 bands. As band 7 (2.08-2.35µm) is an important band for segregation of geologic rock formations especially, it would be efficient for distinguishing hydrothermal alteration area. By using ENVI (Environment for Visualizing Images) software, the lithology of area was segregated (as 4 main units and 12 subunit) and the software provided a means of estimating mineral abundance without a past knowledge.
The orthoclase-plagioclase-biotite granitoid stock of Torbat-e-Jam is weakly peraliminous (A/CNK=0.8-1.6) and calcoalcaline (Na2O>K2O).�
The gold-bearing quartz-vein mineralization within the stock was occurred and silicification, sericitization and chloritization of the stock associated with quartz-vein mineralization are enriched in Au, As, K, Mo, Co and Sb. These mineralization fluids may be due to differentiation of the same granitoid magma crystallization at depth. The gold mineralization associated with an antimony mineralization episode.
The samples have Na2O/K2O ratio between 0.7 to 2 as is typical of I-type granitoid rocks. In addition, the specimens have low to intermediate MgO/Feo (T) ratios ranging from 0.3 to 0.9.
The anomalous concentrations of Au (2.4 ppm), Sb (0.9 ppm), Bi (0.15 ppm) and Co (12.8 ppm) in the granitoid are well above of crustal averages suggest that the magma enrichment during of differentiation of granitoid magma crystallization at depth. Based on REE data, the Jam granitoid can be classified as I-type granite as well.
The average trace element abundance of the Jam granitoid is very similar to the I-type granite, average in its low large ion lithophile elements (LILE) contents and high high field strength elements (HFSE) contents.

Subject List : gold

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