INIBIOMA   20415
INSTITUTO DE INVESTIGACIONES EN BIODIVERSIDAD Y MEDIOAMBIENTE
Unidad Ejecutora - UE
artículos
Título:
Revised stratigraphic framework of the Cretaceous in the Bajo Grande area (Argentinean Patagonia) inferred from new U-Pb ages and palynology
Autor/es:
PASSALIA, M.G.; LLORENS, M.; CÉSARI, S.; LIMARINO, C.O.; PÉREZ LOINAZE, V.; VERA, E.
Revista:
CRETACEOUS RESEARCH (PRINT)
Editorial:
ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD
Referencias:
Lugar: Amsterdam; Año: 2015 vol. 60 p. 152 - 166
ISSN:
0195-6671
Resumen:
The revision of the stratigraphy of the Cerro Bayo in the Bajo Grande area (Argentinean Patagonia) and the new 206Pb/238U age of 116.85 ± 0.26 Ma constrain the dating of the Baquero flora, one of the most abundant Aptian floras of southern Gondwana. This flora, preserved in the Baquero Group, represents anextinct biome that flourished ca. 118 Ma ago and was affected by increasing regional volcanism during the subsequent four millions years. The outcrops of the Cerro Bayo are characterized by fluvio-lacustrine deposits divided into three facies associations that include nine lithofacies. The first palynological record for the locality confirms the correlation of the lower part of the outcrops with the Anfiteatro de Tico Formation (the oldest unit of the Baquero Group). The new radiometric age and stratigraphy support recognition of the Bajo Tigre Formation (the middle unit of the Baquero Group) in the area and date theearliest stage in angiosperm diversification in southern South America. Stratigraphic relationships among the Baquero, Chubut and Divisadero groups are briefly discussed.