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 ± 11 Ma), 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 An_pl, Fo_ol, and Mg#_cpx, and in Cr and Ni concentrations of magnetite, albeit with several reversals to more primitive 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 in the late 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 reflecting 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.

铁钛钒 (Fe-Ti-V) 氧化物矿化通常与元古代地块型斜长岩有关，但对其形成所需的条件仍知之甚少。位于加拿大魁北克省格伦维尔省的 Etoile Suite 镁铁质侵入体 (1149 ± 11 Ma) 由层状镁铁质侵入岩组成，与附近的山体型斜长岩同时期。镁铁质侵入体由方方石和橄榄石辉长岩堆积体组成，其中磁铁矿和钛铁矿在底部（A区）和顶部（C区）为间积云，但积云（<30 id=18>2 O ₅ ）和钛铁矿形成半块状氧化物层。从 B 区的底部到顶部，An _pl 、 Fo _ol和 Mg# _cpx以及磁铁矿的 Cr 和 Ni 浓度总体上逐渐减少，尽管有几次逆转为更原始的成分，包括靠近底部的一个C 区。这表明在开放的岩浆室中发生了分级结晶。侵入体在中等f O ₂ (~FMQ 1.1 ± 0.3) 下结晶，导致富钒磁铁矿从相对演化的岩浆中晚期结晶。母岩浆很可能是源自贫乏地幔源的高铝玄武岩，记录了极小的地壳污染，而同时代的地块型斜长岩通常含有斜方辉石，反映了较高程度的地壳污染。结果，苏长岩斜长岩中的 V 矿化在较高的f O ₂下形成，并且相对贫 V 的磁铁矿较早结晶，而由于较低的f O ₂ ，​​曲长橄榄石辉长岩侵入体中的磁铁矿较晚结晶，具有较高的 V 含量。