Element Mobility in Alteration Zones Within Miduk Porphyry Copper Deposit, Shahr – Babak, Kerman, Iran

The Miduk porphyry copper deposit is located in SSE central Iran in the elongated NW-trending median mountain range of Kerman Province (85 km northwest of the Sar-Cheshmeh porphyry copper deposit). It is associated with Miocene quartz-diorite to quartz-monzonite which intruded Eocene volcanosedimentary rocks. Copper mineralization was accompanied by both potassic and phyllic alteration. Field observations and petrographic studies demonstrate that emplacement of the Miduk pluton took place in several intrusive pulses, each with associated hydrothermal activity. In this study the investigated alterations were potassic, transition, phyllic and propylitic. For determine the mass transfer volume it was use isocon analysis that explain the changes quantitatively. The result of applying this method is presenting the elements that named enrichment, depletion and immobile. According to this method and the obtained plots, Si, Ti, Al, Ga were relatively immobile during alteration and the mass changes during these process and alteration were approximately near to zero. In potassic alteration zone there is obvious enrichment of K, Ba and depletion of Na, Ca, Mg and Mn. Potassic alteration was associated with a major addition of Cu, as evident from the occurrence of disseminated chalcopyrite and bornite in this zone. In the transition alteration zone, Ca was added, Cu and K were depleted and Na and Mg were relatively unchanged. One of the reasons for this for loss of K is relative to Na, which reflects the replacement of K-feldespar by albite. In phyllic alteration zone, Na, K and Ba were depleted and Cu, Ca and Fe were enriched. The loss of K and Na reflects the sericitization of alkali feldspar (such hydrothermal biotite that formed in potassic alteration). Finally in the propylitic alteration zone Fe and Ba were depleted and Ca, Mg, Na and Cu were enriched. Depletion of Fe was due to the alteration of Fe-rich magmatic amphibole and biotite, by biotite and phengitic muscovite with appreciably lower Fe/Fe+Mg ratio