Cadomian Iron ore bodies in the Bafq-Saghand metallogenic province, Iran: genetic constraints from field observations and laser ablation ICP-MS mineral studies

ABSTRACT

The volcano-sedimentary unit in the Bafq-Saghand metallogenic province (BSMP) of Central Iran hosts various types of iron ore bodies including Fe-oxides with jaspilite beds, Mn-dominated iron lenses, magnetite-apatite lenses, and massive magnetite-apatite deposits. The Fe-oxides with jaspilite beds and Mn-dominated iron lenses have limited outcrops and show volcano-sedimentary features in the field. The main features are the presence of syngenetic submarine rhyolite-hosted magnetite, lamination and bedding of iron ore body, jaspilite and dropstone. Volcano-sedimentary origin is testified by magnetite composition showing affinity to BIF and positive Eu and negative Ce anomaly. Magnetite-apatite lenses and massive magnetite-apatite deposits that having spatio-temporal correlation form the main economically important deposits. They have magmatic to high-temperature hydrothermal field characteristics (lava flow-like ore bodies, the presence of degassing tubes in ore bodies, occurrence of brecciated texture and developed Na-Ca metasomatism). Mineral composition (enrichment of LREE, magnetite and apatite negative Eu anomaly and Co/Ni < 1 in pyrites) is in agreement with magmatic and high temperature hydrothermal origin. We propose a hydrous and oxidizing mantle derived iron-rich basic magma that formed in an extensional post-collisional setting for origin of Kiruna-type IOA ore bodies of the BSMP. Fe-oxides with jaspilite beds and Mn-dominated iron lenses resulted from degassing or eruption of iron-rich magma during Ediacaran in a submarine environment. However, magnetite-apatite lenses and massive magnetite-apatite deposits formed from an Early Cambrian magmatic-hydrothermal transition system from a magnetite-crystal mush zone.

Graphical abstract

KEYWORDS:

• Iran
• Bafq-Saghand metallogenic province
• Iron mineralization
• volcano-sedimentary iron body
• magmatic-hydrothermal transition iron mineralization

Acknowledgements

We thank Prof. Stern for his help and efficient editorial handling of this paper. We are grateful to Dr. F. Sepidbar and two anonymous reviewers for their constructive comments and suggestions.

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No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/00206814.2023.2238210

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Funding

The author(s) reported there is no funding associated with the work featured in this article.