## 5 Discussion
### Genetic Implications for Vanadium and Cobalt Occurrence in the SAM
We recognized a slight enrichment of V in massive ilmenites (0.17 to 0.24 wt%) with an increase in the Fe content (36-40 wt%) when compared to ilmenite exsolutions' lamellae in magnetite or to ilmenite pseudomorphs after magnetite. Generally, oxide minerals that have the highest Fe/Ti ratio are the richest in (V + Cr + Al), whereas those with the lowest Fe/Ti ratio are the richest in (Mg + Mn) [29; 54; 55; 56]. Cobalt was concentrated mainly as isomorphic substitutions in magmatic pentlandite, pyrrhotite, and chalcopyrite and in secondary minerals such as siegenite, pyrite, bravoite, cubanite, and talnakhite. A constant admixture of cobalt in magmatic pentlandite was observed, ranging from 1 to 15.3 wt% (mean = 4.4 wt%). However, higher cobalt contents at the level of 14 to 30 wt% were found in siegenite, and some lower substitution of Co wasobserved at the level of 3-4 wt% in talnakhite and 1-3 wt% in bravoite. The concentrations of cobalt in pyrrhotite and chalcopyrite were one order lower, in the range of 0.1-0.6 wt% (means = 0.16 and 0.11 wt%, respectively). Pyrrhotite and chalcopyrite also contained nickel substitutions, with mean values of 0.6 and 0.11 wt%, respectively. The low amounts of Co substitutions were also found in cubanite replacing chalcopyrite (maximum 0.14 wt%). The decomposition processes resulted in the disintegration of sulphide solutions such as pyrrhotite \(\pm\) pentlandite \(\pm\) chalcopyrite and the formation of subsequent generations of Fe, Cu, Ni, and Co sulphides and thiospinels (_(Fe Ni) (Co, Ni)\({}_{2}\)S\({}_{4}\)_). The proportions of metals indicated the presence of diadochid substitutions and/or micro overcrowgrowths of several transition phases in pentlandite or pyrrhotite. According to [41], the transition phases represent a mixture of different thiospinels (_(FeCo)\({}_{2}\)S\({}_{4}\)_, _(NiCo)\({}_{2}\)S\({}_{4}\)_, and _(FeNi)\({}_{2}\)S\({}_{4}\)_)) ensoluted from pentlandite. They described the decomposition of pentlandite into unidentified thiospinels (_(Fe,Ni)(Co,Ni)\({}_{2}\)S\({}_{4}\)_ and Ni-mackinawite, that may later cause the formation of Co-rich pyrite [41]. The presence of Co-rich pyrite was also recognized during our EPMA, but we additionally identified siegenite, bravoite, cubanite, and talnakhite (Tables 3 and 4, Figure 11). Cobaliferous pyrite contained from 1 to 8.6 wt% Co (mean = \(\sim\)2 wt%). In the case of the pyrite replacing pyrrhotite, there was no visible increase in cobalt concentration (\(<\)0.1 wt%) compared to primary pyrrhotite. According to [24], during the first stage of accessory or segregation at low contents of interstitial liquid, one can observe high/O\({}_{2}\), and gradual cooling metallic minerals crystallized with silicates. During the second process, Fe-Ti-rich anorthosite-norite magma formed and metallic minerals settled at the bottom of the magma chamber at high temperature and an intermediate oxygen partial pressure. The injection of Fe-Ti-rich magma or tectonic introduction of the partially solidified ore chamber into the upper part of the solidified pluton, followed by an immiscible segregation process, explains the concordant character of major Fe-Ti-V ore bodies with disseminated sulphides (Fe, Cu, Co, Ni) [46; 56]. Parental ferrodioritic (joint) magma of the SAM anorthosite, enriched in plagioclase and orthopyroxene under high-pressure conditions, is saturated in plagioclase and magnetite-illementie assemblage at the pressure of crystallization of Fe-Ti oxide emplacement [29]. The REE concentrations in the studied ore samples, normalized to chondrite, had very characteristic clear negative Eu and positive Sm anomalies, indicating the common magmatic origin of Fe-Ti-oxides and sulphide mineralizations hosted by anorthosites and norites. We suggest that the crystal sorting of Fe-Ti oxide minerals was responsible for the formation of the SAM Fe-Ti-V deposits relative to plagioclase and ferromagnesian silicates [46; 57].