Early Au-rich sulfide liquid saturation explains the low Au endowment of continental intraplate alkaline magmas

Abstract Alkaline magmatic systems formed in intraplate settings have a low Au endowment, contrasting with the high fertility of alkaline arc and rift settings, which host numerous Au-rich porphyries Cu-Au Au-Ag epithermal deposits. Among other factors, system is determined by concentration ore-forming magma, strongly controlled amount chemistry sulfides that fractionated during magma differentiation. To better explore factors controlling endowment we studied sulfide silicate melt inclusions hosted various phenocrysts from Mont-Dore Massif (France). The was saturated Cu-poor, liquid its differentiation basanite to trachyandesite, leading strong depletion both Cu residual melt. This presumably reduced capacity form magmatic-hydrothermal Such evolution contrasts previous studies conducted sulfide-saturated where an Au-poor monosulfide solid solution main phase crystallize, only marginally affecting budget those systems. We conclude observed saturation volcanic products could explain