Original scientific paper
https://doi.org/10.17794/rgn.2026.3.11
ORE GENESIS AND HYDROTHERMAL EVOLUTION OF THE CHESHMEH-HADI STRATABOUND (MANTO-TYPE) COPPER DEPOSIT IN THE VOLCANIC-PLUTONIC BELT NORTH OF THE DORUNEH FAULT, EAST OF THE SEPID-SARVE COPPER DEPOSIT (NW BARDESKAN, CENTRAL IRAN): EVIDENCE FROM GEOLOGY, GEOCHEMISTRY, FLUID INCLUSIONS, AND STABLE S AND O ISOTOPES
Morteza Esform
; Department of Geology, Faculty of Science, Lorestan University, Khorramabad, Iran.
Hasan Zamanian
; School of Geology, College of Science, University of Tehran, Tehran, 1417935840, Iran.
*
Alireza Zarasvandi
; Department of Geology, Faculty of Earth Sciences, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
Alireza Almasi
; Department of Geology, Faculty of Science, Lorestan University, Khorramabad, Iran.
Mahya Nia
; Department of Geology, Faculty of Science, Lorestan University, Khorramabad, Iran.
* Corresponding author.
Abstract
The Cheshmeh-Hadi copper deposit is part of an Eocene volcano-sedimentary sequence located in the southern Sabzevar Zone. The lithostratigraphic sequence, from oldest to youngest, comprises basalt, basaltic andesite, andesite and pyroxene andesite, conglomerate, limestone, siltstone, gypsiferous marl, and Pliocene conglomerate. The mineralized one occurs within the conglomerate and at the contact between the conglomerate and andesite. The ore minerals consist of malachite-azurite, chalcocite, bornite, covellite and occasionally native copper. The associated hydrothermal fluids show moderate to high salinities, ranging from 3.09 to 13.39 wt.% NaCl equivalent, with homogenization temperatures between 89 and 387°C, indicating fluid mixing during ore formation. Chalcocite is rarely accompanied by quartz, suggesting low silica content in the ore-forming fluids. The δ³⁴S values of sulfide samples from the study deposit range from −24.1‰ to −2.6‰, while δ³⁴S values of hydrothermal H₂S range from −24.3‰ to −2.6‰. The δ¹⁸O values of hydrothermal fluids associated with mineralization fall within the range of basaltic rocks, meteoric waters, and sedimentary rocks. Geochemical variations in major and trace elements suggest the involvement of continental crustal contamination in the magmatic evolution. The studied volcanic rocks fall within the calc alkaline to shoshonitic fields, formed in a continental arc setting, and are derived from an enriched mantle source influenced by subduction-related fluids. These rocks are characterized by HREE depletion, moderate LREE enrichment, and a weak negative Eu anomaly. Based on the results, the Cheshmeh-Hadi deposit is classified as a stratabound copper sulfide deposit, formed in a volcano-sedimentary setting associated with a subduction-related magmatic arc environment.
Keywords
Cheshmeh-Hadi; Stratabound Copper; Volcanic-Plutonic Belt; Stable Isotopes; Central Iran
Hrčak ID:
347419
URI
Publication date:
26.5.2026.
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