87Sr/86Sr, alkali and alkaline earth element geochemistry of Chichinautzin Sierra, Mexico

Abstract

Contents of alkali (K, Rb and Cs) and alkaline earth (Ba and Sr) elements as well as 17Sr/16Sr ratios are reported. for eight selected samples of basalt and andesite from Chichinautzin Sierra and one sample of older dacite from this area. Trace element data are compatible with fractional crystallization of hornblende, plagioclase, olivine and pyroxenes (in approximately decreasing importance). Initial 17Sr/86Sr ratios range from 0.7034 to 0.704S. In the light of this and other evidence a mantle origin with only a small contribution from altered oceanic crust or sialic continental crust is favored for the Chichinautzin magmas.