Geología y geoquímica de elementos mayores de la Caldera de Huichapan, Hidalgo, México

Abstract

Huichapan Caldera is around 8.5 km wide. lt is located in the central part of the Mexican Volcanic Belt. This caldera was formed about 4.2 Ma ago by eruption of severa! flows of San Francisco and Don Guinyó ignimbrites . Lithologically four groups have been identified: a sedimentary basemcnt formcd by cretaccous limcstoncs; a prc-caldera scquencc containing basalts and rhyolites of the San Juan Group; a calderic sequence composed of San Francisco and Don Guinyó ignimbrites; anda post-ignimbrite sequence of andesites , dacites and basalts . Fifteen rock sampks were selccted for major elcment analysis by X-ray fluorescence spectrometry. Chemically, these rocks vary from basaltic andesites to rhyolites. They belong to the calc-alkaline and high-K calc-alkaline series. In thcir major element features they are similar to those of Amealco Caldera.