Abstract

SEGGIARO, Raúl et al. Neotectónica y volcanismo monogenético cuaternario sobre el segmento central del lineamiento Calama Olacapato Toro, NO Argentino. Rev. Asoc. Geol. Argent. [online]. 2016, vol.73, n.4, pp.468-477. ISSN 0004-4822.

Two sections of quaternary deposits in the vicinity of San Antonio de los Cobres at the Puna of Salta are described. These deposits allow relating neotectonics of the central segment of the Calama - Olacapato - Toro lineament with the basic quaternary magmatism erupted in the region. The paraje Corte Blanco section, east of San Antonio de los Cobres, consists of alluvial fan deposits with abundant supply of basaltic ashes and the Chorrillos area section, WNW of San Antonio de los Cobres, is represented by a succession of basaltic pyroclastic deposits of surges and ignimbrites that indicate magma-water interaction. The observed mineralogy of the pyroclastic deposits is similar to that recorded at the lavas of the quaternary monogenetic volcanoes Negro de Chorrillos and San Gerónimo, located in the vicinity. Both sections show evidences of liquefaction (interpreted here as seismites) and they are affected by transcurrent and reverse faults which are oblique to the NW-SE strike of the Calama - Olacapato - Toro lineament and are consistent with regional sinistral kinematics. Finally, on the basis of the observed field relationships, we suggest the Negro de Chorrillos volcano as the emission center of the described pyroclastic deposits and that its activity may have been triggered by neotectonic movements.

Keywords : Puna; Quaternary deformation; Monogenetic volcanism; Central Andes; Hydrovolcanism.

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