Continental Rift Setting for the Central Part of the Mexican Volcanic Belt: A Statistical Approach

I prepared compilations of geochemical data from the central part of the Mexican Volcanic Belt (C-MVB), the Central American Volcanic Arc (CAVA) from Guatemala to northwestern Costa Rica, the continental arc of the Andes in South America, other mostly island arcs, extensional and continental break-up regions, and continental rifts. Using quanti- tative statistical methods, the origin of the C-MVB is constrained as a continental rift. Specifically, this continental rift setting for the C-MVB is inferred from conventional bivariate discrimination diagrams, new natural logarithm- transformed correct statistics-based discriminant function diagrams, quantitative Nb/Nb* parameter, and 99% confidence limits of the mean for the ratios of slab- or continental crust-sensitive and mantle-sensitive parameters. The subduction- related models based on qualitative interpretations most commonly proposed for the Mexican Volcanic Belt in the litera- ture are not supported from these robust quantitative constraints. All geological, structural, geochemical, isotopic (Sr, Nd, Pb, Os, and Be), and geophysical data are in fact consistent with this statistics-based conclusion of the continental rift set- ting and exclude involvement of the subducted slab from the genesis of the C-MVB magmas.