摘要：Quantitatively evaluating of mass changes of major and minor elements that accompanied alteration in granodioritic rocks of Darrehzar porphyry copper deposit based on elements that were immobile during alteration is the aim of study that is done for the first time. Darrehzar porphyry copper deposit has four distinct types of hypogene alterations: Potassic, Phyllic, Argillic and Propylitic. Mineralogic study of these ore bodies distinguished an upper oxidation zone, an intermediate enriched zone and a primary sulfide zone. Copper mineralization was accompanied by both potassic and phyllic alterations. Supergene alteration was minor and restricted to a thin blanket of Cu sulfides under an argillic cap. Isocon plots illustrate that Al, Ti and Ga were relatively immobile during alteration and the mass was essentially conserved during alteration. At all stages in the evolution of the hydrothermal system, TiO2 and Al2O3 which are immobile and have a high correlation coefficient are used in the calculations. In the potassic alteration zone there is an obvious enrichment in K and depletion in Na, Ca, Mn and Fe. These changes were due to replacement of plagioclase and amphibole by K-feldspar and biotite, respectively. Potassic alteration was associated with a large increase in Cu represented by disseminated chalcopyrite and bornite in this zone. Phyllic alteration was accompanied by the depletion of Na, K, Fe and Ba and the enrichment of Si and Cu. The loss of Na, K and Fe reflects the sericitization of alkali feldspar and the destruction of ferromagnesian minerals. The addition of Si is consistent with widespread silicification which is a major feature of phyllic alteration and the addition Cu, mobilized from the potassic zone which is depleted in this element.
