C and O stable isotopes and rare earth elements in the Devonian carbonate host rock of the Pivehzhan iron deposit, NE Iran
Najafzadeh Tehrani, P. (University of Tabriz. Department of Earth Sciences)
Calagari, A. A. (University of Tabriz. Department of Earth Sciences)
Velasco Roldan, Francisco (Universidad del País Vasco. Departamento de Mineralogía y Petrología)
Simmonds, V. (University of Tabriz. Research Institute for Fundamental Sciences)
Siahcheshm, K. (University of Tabriz. Department of Earth Sciences)

Date:	2018
Abstract:	The Pivehzhan iron deposit is located at about 80km southwest of Mashhad, NE Iran. It occur within the Devonian carbonates as lenticular and massive bodies, as well as veinlets of magnetite and iron sulphides, transformed to goethite and haematite by weathering process. The hydrothermal calcite is the most important gangue mineral, which is observed in the form of veins/veinlets and open-space filling. The iron ores are accompanied by some minor elements such as Mn, Ti, Cr, and V and negligible amounts of Co and Ni. The distribution pattern of Rare Earth Elements (REEs) normalized to Post Archean Australian Shale (PAAS), which is characterized by the upward convex, as well as the positive Eu anomalies indicate the activity of reduced and acidic hydrothermal fluids. The negative Ce anomalies of host carbonates, although slight, point to the dominance of anoxic conditions during interaction with hydrothermal fluids. The hydrothermal calcite and quartz coexisting with the iron minerals contain principally fluid, which were homogenized into a liquid phase. The Homogenization Temperature (TH) and the salinity of the analysed fluid inclusions range from 129°C to 270°C and from 0. 4wt. % to 9. 41wt. % NaCl eq. , respectively. The δ13CPDB and δ18OSMOW values range from -2. 15‰ to -5. 77‰ (PeeDee Belemnite PDB standard) and from +19. 87‰ to +21. 64‰ (Standard Mean Ocean Water SMOW standard) in hydrothermal calcite veinlets occurring with iron minerals, and from -0. 66‰ to -4. 37‰ (PDB) and from +15. 55‰ to +20. 14‰ (SMOW) within the host carbonates, respectively. The field relations and petrographic examination along with geochemical and isotopic considerations indicate that the Pivehzhan iron deposit was formed through replacement processes by reducing and acid fluids containing light carbon and oxygen isotopes. Variations in the physico-chemical conditions of hydrothermal fluids and their interaction with carbonates were the most effective mechanisms in the formation of this iron deposit. The potential source of iron was probably the basement magmatic rocks from which iron was leached by hydrothermal solutions.
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Ree geochemistry ; Carbonate host rocks ; C and o stable isotopes ; Pivehzhan ; Iron
Published in:	Geologica acta, Vol. 16 Núm. 2 (June 2018) , p. 125-148 (Articles) , ISSN 1696-5728

Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/338407
Adreça alternativa: https://revistes.ub.edu/index.php/GEOACTA/article/view/GeologicaActa2018.16.2.2
DOI: 10.1344/GeologicaActa2018.16.2.2

24 p, 5.1 MB

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