High-precision late Aptian Pb/U age for the Punta del Barco Formation (Baqueró Group), Santa Cruz Province, Argentina

CÉSARI, S. N.; LIMARINO, C. O.; MAGDALENA LLORENS; MAURO PASSALIA; V.S. PEREZ LOINAZE; EZEQUIEL IGNACIO VERA

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2011 vol. 31 p. 426 - 431

0895-9811

The Baqueró Group holds a rich fossil flora including macrofloristic and palynological remains that characterize the Early Cretaceous vegetation of Argentina. The age of the upper part of the Group, known as Punta del Barco Formation, has been a topic of several discussions in the past. The type locality of this stratigraphic unit exposes fossiliferous tuffs together with muddy tuffs and tuffaceous sandstones beds. However, there have been no reliable age constraints for the fossil assemblages. 206Pb/238U analyses of zircon crystals yielded an age of 114.67  0.18 Ma. This age control makes possible an improved analysis and comparison of the floras in the southern region.