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Vol.:(0123456789)
Mineralium Deposita (2025) 60:323–349
https://doi.org/10.1007/s00126-024-01298-9
ARTICLE
Petrogenesis ofthe1149Ma Etoile Suite Mafic Intrusion,
Quebec: implications forvanadium mineralisation inProterozoic
anorthosite‑bearing terranes
RandolphP.Maier1 · SarahA.S.Dare1· WilliamD.Smith2,3
Received: 2 January 2024 / Accepted: 9 July 2024 / Published online: 10 August 2024
© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024
Abstract
Iron-titanium-vanadium (Fe-Ti-V) oxide mineralisation is commonly associated with Proterozoic massif-type anorthosites,
but the conditions required for their formation remain poorly understood. The Etoile Suite Mafic Intrusion (1149 ± 11Ma),
in the Grenville Province, Quebec (Canada), comprises a layered mafic intrusion that is coeval with nearby massif-type
anorthosites. The mafic intrusion consists of troctolite and olivine gabbro cumulates, where magnetite and ilmenite are
intercumulus at the base (Zone A) and top (Zone C) but cumulus (<30 modal %) in the centre (Zone B). Towards the base of
Zone B, vanadium mineralisation occurs in a 1-km-thick oxide-rich wehrlite horizon, where V-rich titanomagnetite (<1.85
wt% V2O5) and ilmenite form semi-massive oxide layers. From the base to the top of Zone B there is an overall progressive
decrease in Anpl, Fool, and Mg#cpx, and in Cr and Ni concentrations of magnetite, albeit with several reversals to more primi-
tive compositions, including one near the base of Zone C. This indicates fractional crystallisation in an open magma chamber.
The intrusion crystallised at moderate fO2 (~FMQ 1.1 ± 0.3), resulting inthelate crystallisation of V-rich magnetite from a
relatively evolved magma. The parental magma was likely a high-Al basalt derived from a depleted mantle source, recording
minimal crustal contamination, in contrast to coeval massif-type anorthosites that commonly contain orthopyroxene reflect-
ing higher degrees of crustal contamination. As a result, V mineralisation in noritic anorthosites formed at higher fO2, with
early crystallisation of relatively V-poor magnetite, whereas magnetite in troctolitic-olivine gabbroic intrusions crystallised
later with higher V contents, due to lower fO2.
Keywords Fe-Ti-V oxide mineralisation· Layered intrusion· Magnetite· Oxygen fugacity· Proterozoic massif-type
anorthosite· Trace elements
Introduction
Magmatic iron-titanium-vanadium (Fe-Ti-V) oxide deposits
are the most important source of Ti and V globally (Kelley
etal. 2017; Woodruff etal. 2017), but the processes required
to accumulate oxides into massive layers/lenses remains a
debate (Cameron 1980; Wilson etal. 1996; Robinson etal.
2003; Charlier and Grove2012; Charlier etal. 2015; Maier
etal. 2013; Zhou etal. 2013; Howarth and Prevec 2013). Fe-
Ti-V deposits can be subdivided into two types, namely those
hosted in layered mafic-ultramafic intrusions (e.g., Bush-
veld Complex, South Africa: Klemm etal. 1985; Panzhihua,
China: Pang etal. 2008), and those hosted in Proterozoic
massif-type anorthosites (e.g., Lac-Saint-Jean: Grant 2020;
Northwest River: Valvasori etal. 2020; Suwalki: Charlier
etal. 2009). Layered mafic-ultramafic intrusions are typically
associated with large igneous provinces (Ernst etal. 2019;
Smith and Maier 2021; Latypov etal. 2023) which, in turn,
tend to be associated with mantle plumes and intraplate tec-
tonic settings (Bryan and Ernst 2008). As a result of differen-
tiation, the intrusions display a wide range of rock types, rang-
ing from ultramafic (peridotite, pyroxenite), to mafic (norite,
gabbronorite, troctolite, anorthosite), and to more evolved
Editorial handling: E. Mansur
* Randolph P. Maier
randolph.maier@gmail.com
1 Département des Sciences Appliquées, Université du Québec
à Chicoutimi (UQAC), Saguenay, QuébecG7H2B1, Canada
2 Department ofEarth Sciences, Herzberg Laboratories,
Carleton University, Ottawa, OntarioK1S5B6, Canada
3 School ofEarth & Environmental Sciences, Cardiff
University, CardiffCF103AT, UK
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