Petrographic and Geochemical Characterization of Chlorite and Epidote in the Propylitic Alteration Zone of the Meiduk Cu-Mo-Au Porphyry deposit, Kerman Province, Iran; An Approach for Vectoring Porphyry System

Ghorbani Shadpay, Raheleh; Behzadi, Mehrdad; Wilkinson, Jamei; Maanijou, Mohammad; Mohammaddost, Hadi

doi:10.22071/gsj.2026.586398.2257

Petrographic and Geochemical Characterization of Chlorite and Epidote in the Propylitic Alteration Zone of the Meiduk Cu-Mo-Au Porphyry deposit, Kerman Province, Iran; An Approach for Vectoring Porphyry System

Articles in Press

Document Type : Original Research Paper

Authors

Raheleh Ghorbani Shadpay ¹

Mehrdad Behzadi ¹

Jamei Wilkinson ²

Mohammad Maanijou ³

Hadi Mohammaddost ⁴

¹ Department of Mineral and Ground Water Resources, Faculty of Earth Science, Shahid Beheshti University, Tehran, Iran

² Department of Earth Science and Engineering, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom.

³ Department of Geology, Faculty of Basic Sciences, Bu-Ali Sina University, Hamedan, Iran

⁴ Department of Mineral Exploration and Development, National Iranian Copper Industries Company (NICICO), Iran

10.22071/gsj.2026.586398.2257

Abstract

The Meiduk mineralization is associated with two intrusive bodies of quartz diorite–quartz monzonite composition and a granodiorite body that intruded Eocene volcanic–sedimentary rocks. Chlorites are predominantly clinochlore and their compositions reflect two main substitution mechanisms: (1) Tschermak coupled substitution and (2) strong Mg²⁺↔Fe²⁺ exchange, indicating a solid-solution series. Epidotes show intermediate compositions between clinozoisite and epidote, with variations controlled by complete substitution of Al³⁺ by Fe³⁺ in octahedral sites, confirming oxidizing conditions in the Meiduk porphyry system. The lack of significant correlation between Mn and Fe or Al suggests Mn is mainly incorporated as Mn²⁺ in epidote. Fe in chlorite increases toward the ore center, whereas Mg decreases, a trend differing from other porphyry systems and possibly related to sericitic alteration. From margin to center, Al increases with temperature, while Si shows an opposite trend consistent with lower-temperature conditions. In epidote, Fe³⁺ and Al display inverse variation with distance from mineralization, reflecting solid-solution behavior. Overall, substitution patterns in chlorite and epidote record the physicochemical evolution of hydrothermal fluids and serve as effective vectoring tools toward porphyry mineralization centers, providing reliable indicators for exploration targeting in similar hydrothermal systems.

Keywords

Major Elements

Mineralogy

Chlorite

Epidote

Propylitic Alteration

Meiduk Deposit

Subjects