MACNBR   00242
MUSEO ARGENTINO DE CIENCIAS NATURALES "BERNARDINO RIVADAVIA"
Unidad Ejecutora - UE
capítulos de libros
Título:
Late Miocene palynological assemblages from Patagonia: continental and marine evidence
Autor/es:
BARREDA, VIVIANA; GULER, MARÍA VERÓNICA; PALAZZESI, LUIS
Libro:
Late Cenozoic of Patagonia and Tierra del Fuego
Editorial:
Elsevier
Referencias:
Lugar: Amsterdam; Año: 2007;
Resumen:
The data here analyzed came from outcrop samples from Río Negro (Barranca Final and El Espigón sections, Barranca Final and Río Negro Formations) and Chubut (Puerto Pirámide section, Puerto Madryn Formation) provinces at northeastern Patagonia, and represent the southernmost deposits of the so-called “Entrerriense” sea. Puerto Madryn Formation was deposited about 10 Ma ago considering Sr87/Sr86 ages based on pectinid shells. These data coincide with a previous K40/Ar40 determination of a tuff level from the upper part of the marine sequence. The Barranca Final Formation was considered as Middle-Late Miocene age ranged on the basis of foraminifera stratigraphic distributions. Vertebrate studies from higher levels of the Upper Member of the Río Negro Formation suggested an Early Pliocene, “Montehermosense” Land-Mammal age for these deposits. Other data came from cutting samples of boreholes drilled in the Colorado Basin, penetrating Barranca Final Formation. These palynofloras are difficult to date with precision (cutting samples). They are adequate to compare with other palynological data, though. In spite of the scarcity of suitable pollen data, the main trends of the Late Miocene Patagonian vegetation have been sketched in this chapter.