Geochemical and Isotopic Constraints on the Origin of Mafic Volcanism in Central Mexico

Abstract

Miocene to Recent volcanism in central Mexico is wide-spread mainly in two volcanic provinces (Fig. 1); basaltic to rhyolitic volcanism in eastwest trending Mexican Volcanic Belt (MVB) from the Pacific to the Gulf of Mexico and dominantly mafic volcanism in Los Tuxtlas Volcanic Field (LTVF), presumably a part of Eastern Alkaline Province. The origin of these volcanic provinces and their interrelationship are controversial. Widely varying models have been proposed for the MVB (abundant literature does indeed exist at present), among which the most cited are related to the subduction of Cocos and Rivera plates. The distance of the volcanic front of the MVB from the trench (MAT, Fig. 1) varies from ~ 160 km in the west to ~450 km in the easternmost Veracruz area. The LTVF and the El Chich6n volcano are situated about 380 km and 320 km respectively from the MAT. A systematic study of mafic volcanism should prove helpful in deciphering the origin of these volcanic provinces.