Iron and Fe–Mn mineralisation in Iran: implications for Tethyan metallogeny

Beate Orberger (1) , Christiane Wagner-Raffin Wagner (2) , Omar Boudouma (2) , Colette Derré (2) , Michel Fialin (2) , Johan Neuville (3) , Etienne Deloule (3) , Ghasem Nabatian (4) , Maryam Honarmand (5) , Iman Monsef (5) , Abdolreza Ghods (5)

1 GEOPS - Géosciences Paris Sud
2 iSTeP - Institut des Sciences de la Terre de Paris
3 CRPG - Centre de Recherches Pétrographiques et Géochimiques
4 ZNU - University of Zanjan
5 IASBS - Institute for Advanced Studies in Basic Sciences

The siliceous iron ore deposits in the NW part of Iran (Takab region) are hosted within para-metamorphic rocks, and are attributed to Late Proterozoic age. They comprise massive, banded, nodular and disseminated ore types, which are mainly composed of magnetite. Magnetite contains traces of Al. It is variously hematitized. Hematite show higher Al, Si and Ca contents than the magnetite. The iron oxides contain inclusions of zircons, apatite, uraninite, Mn-carbonate and euhedral monazite. Later hydrothermal solutions precipitated goethite surrounding the magnetitehematite-maghemite grains and replacing hematite. Barite occurs in fractures of iron oxides, Mn-Ba-Pb oxi-hydroxides and scheelite occur interstitial to iron oxides. The ∂ 56 Fe values observed for magnetite decrease from disseminated to nodular iron ore (averages: +1.3, +0.4 and-0.4 ‰ (± 0.2 ‰), respectively). Iron isotopes of hematite in disseminated & layered ore show higher ∂ 56 Fe values than those of magnetite, in the range of +2 to +4 ‰ (± 0.2 ‰).

Mots clés: Iron ore Iran; iron isotopes; rare-earth elements

Domaines: Minéralogie; Pétrographie; Géochimie

Beate Orberger, Christiane Wagner-Raffin Wagner, Omar Boudouma, Colette Derré, Michel Fialin, et al.. Iron and Fe–Mn mineralisation in Iran: implications for Tethyan metallogeny. Australian Journal of Earth Sciences, 2015, 62 (2), pp.211-241. ⟨10.1080/08120099.2015.1002001⟩. ⟨hal-03521411⟩