Origin of the Vanadiferous Serpentine–Magnetite Rocks of the Mt. Sorcerer Area, Lac Doré Layered Intrusion, Chibougamau, Québec

Geosciences. 2019;9(3):110 DOI 10.3390/geosciences9030110


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Journal Title: Geosciences

ISSN: 2076-3263 (Print)

Publisher: MDPI AG

LCC Subject Category: Science: Geology

Country of publisher: Switzerland

Language of fulltext: English

Full-text formats available: PDF, HTML



Lucie Mathieu (Centre D’études sur les Ressources Minérales (CERM), Département des Sciences Appliquées, Université du Québec à Chicoutimi (UQAC), 555 blvd. de l’université, Chicoutimi, QC G7H 2B1, Canada)


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Time From Submission to Publication: 11 weeks


Abstract | Full Text

Magmatic processes dominate Fe&#8315;Ti&#8315;V mineralization and revealing these processes is essential for providing a scientific foundation for exploration models. This study focuses on the metamorphosed Neoarchean (ca. 2728 Ma) tholeiitic layered Lac Dor&#233; Complex (LDC) that is currently being explored for V. Contamination may play an important role in the evolution of the Fe&#8315;Ti&#8315;V-enriched layered zone (magnetitite, anorthosite, and gabbro mostly, and ultramafic rocks locally) of the LDC. This hypothesis is tested by performing a detailed chemical and petrological investigation of serpentine-magnetite-dominated rocks located in the Mt. Sorcerer area. The studied rocks have evolved (apatite-bearing, Fe-rich, Cr-Ni-Ti-poor) and primitive (Mg-rich, Si-poor) characteristics. Pre-metamorphism rocks contained olivine Fo<sub>82&#8315;90</sub> (now serpentine) and magnetite. These rocks formed from a Si-depleted magma under high fO<sub>2</sub> conditions (+1.8 to +3.0 relative to the fayalite-magnetite-quartz buffer; FMQ). The V-content of the magnetite varies due to reversals related to multiple injections of an evolved basaltic magma in the upper part of the LDC. The magma interacted with Fe-Mg-rich and Si-Ca-poor carbonate-facies iron formation and crystallized in the presence of oxidizing CO<sub>2</sub>-bearing fluids. Compositional layering is poorly defined due to a fast cooling rate. Consequently, the distribution of V is relatively homogeneous in the Fe&#8315;Mg-rich units of the Mt. Sorcerer area.