Combined U-Pb and Lu-Hf isotope study from the Las Lozas volcanics, northwestern Argentina: evidence of juvenile Cryogenian-derived, lower Pennsylvanian volcanism in western Gondwana.

ZAPPETTINI, E.O., COIRA, B., SANTOS, J.O.S., CISTERNA, C.E. AND E., BELOUSOVA

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2015 vol. 59 p. 13 - 18

0895-9811

Las Lozas volcanic succession, cropping out in the southwestern Puna, Catamarca province, Argentina, consists of an intracontinental volcanic sequence of Carboniferous age. The lavic members are predominantly rhyolites, and subordinated andesites and basalts. The volcaniclastic layers consist of monomictic and polymictic breccias with structures denoting processes of lava fragmentation. They constitute a bimodal suite, ranging from basalts to high silica rhyolites. A new UePb SHRIMP age of 320 ± 2 Ma for a rhyolite allows extending the Mississipian magmatism of the region to the lower Pennsylvanian. Hf data point to juvenile sources of Cryogenian age with no evidence of older reworked crustal contamination.