Geochronology of Mexican mineral deposits. III: the Taxco epithermal deposits, Guerrero

Resumen

New 40Ar/39Ar (34.96 ±
0.19 Ma) and U-Pb ages (35.44 ± 0.24 and 34.95 ± 0.37 Ma) obtained
in this study for the Calavera group of dikes, which predate
intermediate sulfidation epithermal mineralization in the Taxco
mining district, constrain the formation of such deposits to less
than 34.96 Ma (latest Eocene). These deposits might arguably have
formed at ~ 33 Ma, thus coinciding in age with the La Azul fluorite
deposits, within the same district. Although this age is
significantly younger than previously existing estimations, the
deposits at Taxco consistently cluster into a Late Eocene to
Oligocene metallogenic event. Such event was closely associated with
the volcanism in the northern part of the Sierra Madre del Sur,
specifically to the most prominent flare-up of subduction-derived
volcanism before it ceased in the region and refashioned into the
Trans-Mexican Volcanic Belt.