Writers : Shokri, R.; Khakzad, A.; Razmara, M
Refference : 29th symposium on geosciences, p:91
Publishing Year : 1389

Abstract :

The petrogenetic, mineralography and geochemical studies of Bomabad area showed close relationships between mineralization and intrusive bodies as well as faulting. The mineralization is occurred as primary and secondary styles. The primary ores were appeared as sulfides and oxides and includes pyrite, chalcopyrite, galena and magnetite. The secondary minerals are as followings: hematite, malachite, azurite and iron and manganese hydroxides. On the basis of petrological studies, three types of mineralization were characterized in the area: 1) mineralization related with intrusive rocks (intrusion of microdiorite into quartizitic sandstones of Taknar formation). 2) mineralization related with faulting (a network of fractures and basin controlling faults). 3) mineralization along of silicious veins. The petrological studies showed a differentiation trend from basic (with gabbro and diorite compositions) to intermediate (with granodiorite and monzogranite) and finally acidic (quartz syenite and syenogranite). As plotted in different petrological diagrams, an interesting result was obtained. The magma which formed these bodies was caicaikaiine and peraiuminous. The combination of structural and petrological diagrams revealed arc position and I type granitoides series for intrusive rocks.
At the area, the genesis of the mineralization is considered to be a combination of ascending hydrothermal fluids and later epigenetic processes. Large volumes of oxidized siliceous fluids were introduced into the Taknar Formation sediments and penetrated upwards into the reducing overlying sandstones, via a network of fractures, basin controlling faults, and rock permeability contrasts. Early mineralization is formed by this fluid movement, which is dependent on permeability, chemical buffering and the speed with which the fluids migrate through the rock. The slower these fluids moved, the greater the time afforded to the precipitation of copper and Gold. This study showed that a later stage epigenetic phase of mineralzation occurred throughout the area.

Subject List : Copper, Mineralization, Geochemistry, Copper