Thermal post-depositional evolution of the Neoproterozoic-Paleozoic pelites of the northwest Argentina and their implications for the early Paleozoic evolution of the SW Gondwana margin

PAMELA ALEJANDRA APARICIO GONZÁLEZ; AGNES IMPICCINI; ANDREA BARRIENTOS; CLAUDIO DE MORISSON VALERIANO; MONICA HEILBRON; NATALIA HAUSER; REIMOLD, W

General Roca

Otro; XVI Reunión Argentina de Sedimentología; 2018

Asociación Argentina de Sedimentología

A comparative analysis of the thermal post-depositional evolution of metapelitic of the Paleozoic succession (Puncoviscana Complex (PC), Santa Victoria and Mesón Groups) in the Central Andes of northwestern Argentina was estimated through Xray diffraction of clay minerals analysis and Kübler Index (KI). The results indicate variation between diagenetic-epizone grade for the south Neoproterozoic ? Lower Paleozoic succession. This results are similar known in the north of Cordillera indicate that the diagenesis-metamorphic grade is uniformity for the Cordillera Oriental. XRD-based studies of metapelitic rocks of the Paleozoic sequence indicate the presence of illite, mica/chlorite, kaolinite and chlorite/smectite. The origin of the clay minerals could be associated to volcanic ash and others probable indicate retrograde reactions. Probable k-bentonite was identified in white-yellow layers of the pelite of the San Bernardo Formation (Tremadocian-Flonian) associate with the Faja eruptiva de la Puna.