Mineral chemistry of apatite, amphibole, biotite, and magnetite from the Masjeddaghi porphyry Cu-Au deposit, NW Iran: petrogenetic and metallogenic implications

The Masjeddaghi porphyry Cu-Au deposit is situated in the Alborz-Azarbaijan structural zone of northwest Iran. Chemical compositions of rock-forming (biotite, amphibole) and accessory minerals (magnetite, apatite) in the potassic to propylitic altered diorite porphyry of Masjeddaghi serve as key ind...

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Main Authors: Zohreh Rahnama, Shohreh Hassanpour, Dany Savard, Zahid Shah
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-06-01
Series:Frontiers in Earth Science
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Online Access:https://www.frontiersin.org/articles/10.3389/feart.2025.1603296/full
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author Zohreh Rahnama
Shohreh Hassanpour
Dany Savard
Zahid Shah
author_facet Zohreh Rahnama
Shohreh Hassanpour
Dany Savard
Zahid Shah
author_sort Zohreh Rahnama
collection DOAJ
description The Masjeddaghi porphyry Cu-Au deposit is situated in the Alborz-Azarbaijan structural zone of northwest Iran. Chemical compositions of rock-forming (biotite, amphibole) and accessory minerals (magnetite, apatite) in the potassic to propylitic altered diorite porphyry of Masjeddaghi serve as key indicators of magmatic-hydrothermal mineralization. In situ LA-ICP-MS was conducted to analyze trace element contents of selected magnetite-bearing samples, while EMPA analyzed biotite, amphibole, and apatite compositions. The mineral compositions show a parental magma with calc-alkaline features, suggesting a source comprised of both subduction mantle-derived and crust-derived materials, and the Masjeddaghi mineralizing magmas have a relatively elevated ƒO2 and are classified as oxidized I-type magmas. The calculated temperature ranges are constrained by Al-in-amphibole geothermometry, saturation temperature of apatite, and the Ti-in-biotite geothermometer (830°C–877°C) (845°C-918°C) and (723°C–782°C), respectively, whereas the Al-in-amphibole geobarometry exhibits formation pressure (120–186 MPa; relating to depths ranging from 4 to 10 km) and H2Omelt content at time of crystallization (4.10–4.46 wt%), indicating formation of a hydrous calc-alkaline magma from a deep magmatic reservoir. The intrusion of oxidized hydrous mafic magma from a deeper magma source likely promoted wide magma mixing and prolonged fractional crystallization within the evolved dioritic magma chamber, resulting in exsolution of the ore-forming fluids and the formation of the Masjeddaghi deposit.
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spelling doaj-art-b6aac2cce9a347ccb5c53a67af00f7fb2025-08-20T03:27:43ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632025-06-011310.3389/feart.2025.16032961603296Mineral chemistry of apatite, amphibole, biotite, and magnetite from the Masjeddaghi porphyry Cu-Au deposit, NW Iran: petrogenetic and metallogenic implicationsZohreh Rahnama0Shohreh Hassanpour1Dany Savard2Zahid Shah3ANGLO REM CA Exploration Mining Ltd, Astana, KazakhstanDepartment of Geology, Payame Noor University, Tehran, IranLabMaTer, UQAC Laboratory, Université du Québec à Chicoutimi, Saguenay, QC, CanadaSchool of Mining and Geosciences, Nazarbayev University, Astana, KazakhstanThe Masjeddaghi porphyry Cu-Au deposit is situated in the Alborz-Azarbaijan structural zone of northwest Iran. Chemical compositions of rock-forming (biotite, amphibole) and accessory minerals (magnetite, apatite) in the potassic to propylitic altered diorite porphyry of Masjeddaghi serve as key indicators of magmatic-hydrothermal mineralization. In situ LA-ICP-MS was conducted to analyze trace element contents of selected magnetite-bearing samples, while EMPA analyzed biotite, amphibole, and apatite compositions. The mineral compositions show a parental magma with calc-alkaline features, suggesting a source comprised of both subduction mantle-derived and crust-derived materials, and the Masjeddaghi mineralizing magmas have a relatively elevated ƒO2 and are classified as oxidized I-type magmas. The calculated temperature ranges are constrained by Al-in-amphibole geothermometry, saturation temperature of apatite, and the Ti-in-biotite geothermometer (830°C–877°C) (845°C-918°C) and (723°C–782°C), respectively, whereas the Al-in-amphibole geobarometry exhibits formation pressure (120–186 MPa; relating to depths ranging from 4 to 10 km) and H2Omelt content at time of crystallization (4.10–4.46 wt%), indicating formation of a hydrous calc-alkaline magma from a deep magmatic reservoir. The intrusion of oxidized hydrous mafic magma from a deeper magma source likely promoted wide magma mixing and prolonged fractional crystallization within the evolved dioritic magma chamber, resulting in exsolution of the ore-forming fluids and the formation of the Masjeddaghi deposit.https://www.frontiersin.org/articles/10.3389/feart.2025.1603296/fullbiotiteamphiboleapatitemagnetiteMasjeddaghi porphyry Cu-Au depositIran
spellingShingle Zohreh Rahnama
Shohreh Hassanpour
Dany Savard
Zahid Shah
Mineral chemistry of apatite, amphibole, biotite, and magnetite from the Masjeddaghi porphyry Cu-Au deposit, NW Iran: petrogenetic and metallogenic implications
Frontiers in Earth Science
biotite
amphibole
apatite
magnetite
Masjeddaghi porphyry Cu-Au deposit
Iran
title Mineral chemistry of apatite, amphibole, biotite, and magnetite from the Masjeddaghi porphyry Cu-Au deposit, NW Iran: petrogenetic and metallogenic implications
title_full Mineral chemistry of apatite, amphibole, biotite, and magnetite from the Masjeddaghi porphyry Cu-Au deposit, NW Iran: petrogenetic and metallogenic implications
title_fullStr Mineral chemistry of apatite, amphibole, biotite, and magnetite from the Masjeddaghi porphyry Cu-Au deposit, NW Iran: petrogenetic and metallogenic implications
title_full_unstemmed Mineral chemistry of apatite, amphibole, biotite, and magnetite from the Masjeddaghi porphyry Cu-Au deposit, NW Iran: petrogenetic and metallogenic implications
title_short Mineral chemistry of apatite, amphibole, biotite, and magnetite from the Masjeddaghi porphyry Cu-Au deposit, NW Iran: petrogenetic and metallogenic implications
title_sort mineral chemistry of apatite amphibole biotite and magnetite from the masjeddaghi porphyry cu au deposit nw iran petrogenetic and metallogenic implications
topic biotite
amphibole
apatite
magnetite
Masjeddaghi porphyry Cu-Au deposit
Iran
url https://www.frontiersin.org/articles/10.3389/feart.2025.1603296/full
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AT shohrehhassanpour mineralchemistryofapatiteamphibolebiotiteandmagnetitefromthemasjeddaghiporphyrycuaudepositnwiranpetrogeneticandmetallogenicimplications
AT danysavard mineralchemistryofapatiteamphibolebiotiteandmagnetitefromthemasjeddaghiporphyrycuaudepositnwiranpetrogeneticandmetallogenicimplications
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