New 40Ar/39Ar ages from the Central Part of the Chiapanecan Volcanic Arc, Chiapas, México

Abstract

The Chiapanecan Volcanic Arc (CVA), located in the central portion of the State of Chiapas, is a 150 km long chain of volcanic structures aligned in a NW-SE direction. The central part of the CVA is composed of an irregular northeast-trending alignment of more than 10 volcanic structures, generally centered along NNW-SSE trending faults splayed from the Motagua-Polochic Fault System. Among these structures are seven volcanic domes (Huitepec, Amahuitz, La Iglesia, Mispía, La Lanza, Venustiano Carranza, and Santotón), one explosion crater (Navenchauc), one collapse structure (Apas), and one dome complex (Tzontehuitz). In this work, we report thirteen new ages of rocks from seven domes that increase the available geochronometric data on Quaternary volcanic activity in the central part of Chiapanecan Volcanic Arc. From the new and previous data, we identified the Tzontehuitz Dome Complex as the oldest volcanic center in the CVA, yielding an age of 2.1 Ma, and the Venustiano Carranza Volcanic Dome as exhibiting the most recent activity in the zone, with an age of 0.225 Ma.