Sr-Nd-Pb isotope and trace element geochemistry of calc-alkaline andesites from Volcán Colima, Mexico

Abstract

We report Sr, Nd and Pb isotopic compositions and trace clement data on calc-alkaline andesites from Volcan Colima and compare them with other volcanic centers of the Mexican Volcanic Belt. The chondritc-normalizcd REE patterns of Colima andesites show LREE-cnriehment with negligible Eu anomalies. MORB and primitive mantle nor~alizcd multi-clement plots show negative Ta and Ti anomalies in Colima andesites. The isotope ratios ran,gc from 0.70355-0.70358 for 87Sr/86Sr, 0.51295-0.51298 for 143Nd/144Nd, and 18.57-18.59, 15.56-15.58 ~md 38.27-38.31 for 2( PbP114Pb, 207J>bf204Pb, and 208pbf204Pbrespcc-tivcly. The Sr and Pb isotope ratios arc considerably lower and 143Nd/144Nd higher than in most andesites from the Mexican Volcanic Belt.