(Evidence of a major caldera structure related to the Los Azufres geothermal centre, Mexico).

Abstract:

The Sierra Los Azufres (approx= 140 km2) towers over a volcanic complex (approx= 700 km2) consisting of dacitic to rhyolitic domes, calc-alkaline lava-flows and siliceous pyroclastic products, overlying an andesitic basement. Four series of ash and pumice flows, alternating with lava flows, were recognized inside and outside the massif. Their successive outpourings induced the collapse of the central part of the complex, followed by minor faulting, reaching several 100 m. The caldera, about 20 km wide, is surrounded by concentric fracture zones which affect the basement. Volcanoclastic deposits (cinerites) were observed inside the caldera and in basins around the complex. In this context, the Sierra Los Azufres, where the active geothermal center is lying, appears as the resurgent zone. Thus, this geothermal field is related to a caldera of resurgent type.-English summary Centre de Recherches Volcan, Univ Clermont-II-CNRS, 63038 Clermont-Ferrand, France.

Año de publicación:

1985

Keywords:

Fuente:

scopus