Age constrains for the northernmost outcrops of the Triassic Cuyana Basin, Argentina

MANCUSO, ADRIANA; CHEMALE, FARID; AVILA, N.; BARREDO, SILVIA; OTTONE, EDUARDO; MARSICANO, CLAUDIA

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

Elsevier

Lugar: The Netherlands; Año: 2010 vol. 30 p. 97 - 103

0895-9811

Age constraints on the Cerro Puntudo Formation at the northernmost exposures of thecontinental Triassic Cuyana Basin are presented based on palynological data and U-Pbzircon dating. The lacustrine facies of the upper part of the Cerro Puntudo Formation contain a low diverse palynological assemblage that is dominated by spores of ferns and lycopsids with subordinated inaperturated forms of uncertain affinity. The U-Pb SHRIMP zircon age of 243.8 ± 1.9 Ma (Anisian), obtained from juvenile magmatic zircons in a tuff interbedded in the same beds, provides the first chronostratigraphic date of the Cuyana Basin infilling at its northernmost exposures. According to additionaldates already known from the southern part of the basin, a new stratigraphic correlation is proposed thus restricting the first tectono-sedimentary sequence (Synrift Idepositional event of Kokogian et al.) to the Anisian. This depositional event hasalready been recorded in the Cacheuta and Rincón Blanco sub-basins but it is for thefirst time timely constrained across the whole basin.