K/Ar ages of 54 igneous and metamorphic rocks from western, central and southern Mexico

Abstract

Fifty-four samples of igneous and metamorphic rocks from south, central and northern Mexico have been analyzed by the K/Ar method. Samples were provided to Instituto de Geología of Universidad Nacional Autónoma de México by the Consejo de Recursos Minerales (now Servicio Geológico Mexicano) from selected regions of the following states: Baja California Sur, Colima, Durango, Estado de México, Guerrero, Jalisco, Oaxaca, San Luis Potosí, Sinaloa y Zacatecas. All relevant information for each sample, including location, geological unit, petrographical description, mineral analyzed and age is described in the text; analytical data for each sample are given as a table. Ages range from 2 Ma to 249 Ma, with about 30% being Oligocene ages related to volcanism and plutonism in the Sierra Madre Occidental and Sierra Madre del Sur.