Early Cretaceous Zn-Pb (Ba±Ag±Cu±Fe±Mn) Deposits of Iran: Irish Type or Mississippi Valley Type? Reply to Nejadhadad et al. Comment on "Rajabi et al. Barite Replacement as a Key Factor in the Genesis of Sediment-Hosted Zn-Pb±Ba and Barite-Sulfide Deposits: Ore Fluids and Isotope (S and Sr) Signatures from Sediment-Hosted Zn-Pb±Ba Deposits of Iran. Minerals 2024, 14, 671"
Por:
Rajabi, A, Mahmoodi, P, Alfonso, P, Canet, C, Andrew, CJ, Nozaem, R, Azhdari, S, Rezaei, S, Alaminia, Z, Tamarzadeh, S, Yarmohammadi, A, Mohammadi, GK, Kourangi, N, Saeidi, R
Publicada:
11 jun 2025
Resumen:
This study critically examines the early Cretaceous carbonate-hosted Zn-Pb (+/- Ba +/- Cu) deposits of the Malayer-Esfahan (MEMB) and Yazd-Anarak (YAMB) metallogenic belts in Iran, which have been inaccurately classified as Mississippi Valley type (MVT) deposits by Nejadhadad et al. (2025). Our findings reveal significant differences in mineralogy, fluid inclusion characteristics, and geochemical signatures compared to typical MVT deposits. These deposits are more akin to Irish-type Zn-Pb mineralization and formed in extensional and passive margin environments around the Nain-Baft back-arc basin. The normal faults in this back-arc rift can transform significantly during inversion and compressional tectonics, reactivating to behave as reverse faults and leading to new geological structures and landscapes. Our study highlights barite replacement as a crucial factor in forming sediment-hosted Zn-Pb (+/- Ba +/- Cu) and barite-sulfide deposits. Based on textural evidence, fluid inclusion data, and sulfur isotope analyses, we propose that barite plays a fundamental role in controlling subsequent Zn-Pb (+/- Ba +/- Cu) mineralization by serving as both a favorable host and a significant sulfur source. Furthermore, diagenetic barite may act as a precursor to diverse types of sediment-hosted Zn-Pb (+/- Ba +/- Cu) mineralization, refining genetic models for these deposits. Sulfur isotope analyses of Irish-type deposits show a broad delta S-34 range (-28 parts per thousand to +5 parts per thousand), indicative of bacterial sulfate reduction (BSR). Nevertheless, more positive delta S-34 values (+1 parts per thousand to +36 parts per thousand) and textural evidence in shale-hosted massive sulfide (SHMS) deposits suggest a greater role for thermochemical sulfate reduction (TSR) in sulfide mineralization.
Filiaciones:
Rajabi, A:
Univ Tehran, Coll Sci, Sch Geol, Tehran 1417614411, Iran
Mahmoodi, P:
Tarbiat Modares Univ, Fac Sci, Dept Geol, Tehran 14115111, Iran
Alfonso, P:
Univ Politecn Cataluna, Dept Engn Min Ind & TIC, Ave Bases Manresa 61-73, Manresa 08242, Spain
Canet, C:
Univ Nacl Autonoma Mexico, Escuela Nacl Ciencias Tierra, Del Coyoacan 04150, Ciudad De Mexic, Mexico
Nozaem, R:
Univ Tehran, Coll Sci, Sch Geol, Tehran 1417614411, Iran
Azhdari, S:
Univ Tehran, Coll Sci, Sch Geol, Tehran 1417614411, Iran
Rezaei, S:
Ferdowsi Univ Mashhad, Dept Geol, Fac Sci, POB 91775-1436, Mashhad, Iran
Alaminia, Z:
Ferdowsi Univ Mashhad, Dept Geol, Fac Sci, POB 91775-1436, Mashhad, Iran
Tamarzadeh, S:
Univ Tehran, Coll Sci, Sch Geol, Tehran 1417614411, Iran
Yarmohammadi, A:
Tarbiat Modares Univ, Fac Sci, Dept Geol, Tehran 14115111, Iran
Mohammadi, GK:
Univ Tehran, Coll Sci, Sch Geol, Tehran 1417614411, Iran
Kourangi, N:
Univ Tehran, Coll Sci, Sch Geol, Tehran 1417614411, Iran
Saeidi, R:
Univ Tehran, Coll Sci, Sch Geol, Tehran 1417614411, Iran
|