INVESTIGADORES
BORROMEI Ana Maria
artículos
Título:
Changes of the palynobiotas in the Mesozoic and Cenozoic of Patagonia: a review
Autor/es:
QUATTROCCHIO, M.; VOLKHEIMER, W.; BORROMEI, A.M.; MARTINEZ, M.A.
Revista:
Biological Journal of the Linnean Society
Editorial:
Wiley-Blackwel
Referencias:
Lugar: London; Año: 2011 vol. 103 p. 380 - 396
ISSN:
1095-8312
Resumen:
This study describes the compositional changes of MesozoicCenozoic palynologic assemblages in Patagonia, the succession of phytogeographic scenarios and some evolutionary key events. The Triassic Ipswich Microflora, characterized by bisaccate pollen and high frequencies of trilete spores, represents the warmtemperate province of south-western Gondwana (Dicroidium Flora), followed in time, in Patagonia, near the Triassic/Jurassic boundary, by the Classopollis Microflora, indicating warm and (seasonal) arid conditions. Araucariaceans and podocarpaceansgrew on Jurassic uplands. The exclusively Early Cretaceous taxa Cyclusphaera and Balmeiopsis(Coniferae) appeared in the Valanginian. The oldest angiospermous pollen types of Argentina appear in the BarremianAptian of southern Patagonia. During the Maastrichtian, the Nothofagaceae and Myrtaceae are incoming. In the Palaeocene, a vegetation dominated by tropical elements would have developed in Patagonia.Increasing Nothofagidites frequency in northern Patagonia during the Middle to Late Eocene indicates climatic change from warm to temperate. Of three Early to Middle Miocene phytogeographic provinces (NeotropicalTransitional and Austral), the Transitional one was replaced during the Late MiocenePliocene by the xerophytic Proto Espinal/Steppe with a shrubbyherbaceous vegetation. The Pleistocene and Holocene times were characterized by frequent latitudinal and altitudinal changes in the vegetation distribution, as a response to recurrent climatic oscillations, fluctuations of sea level and ice extent, and changing patterns of atmospheric circulation.