Changes of the palynobiotas in the Mesozoic and Cenozoic of Patagonia: a review

Abstract

This study describes the compositional changes of Mesozoic-Cenozoic 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 warm-temperate 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 podocarpaceans grew 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 Barremian-Aptian 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 Miocene-Pliocene by the xerophytic Proto Espinal/Steppe with a shrubby-herbaceous 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.

First occurrence of charophyte algae from a Triassic Paleolake in Argentina and their paleoenvironmental context

“…This is in agreement with the nearly symmetric disposition of Pangaea around the paleoequator during the Triassic (Parrish, 1993). In the southernmost point of the southern hemisphere (Patagonia), during the Triassic, a typical warm-temperate climate (dry summers-wet winters) is recognized by the reconstruction of phytogeographic provinces (Scotese et al, 1999;Quattrocchio et al, 2011). This record allows the expansion of the paleolatitudinal range of Charophyta towards the south and is indicative of a symmetric, paleogeographic distribution pattern around the equator.…”

How lizards survived blizzards: phylogeography of theLiolaemus lineomaculatusgroup (Liolaemidae) reveals multiple breaks and refugia in southernPatagonia and their concordance with other codistributed taxa

“…At this time, the Patagonian climate shifted to cooler conditions (Lisiecki & Raymo ; Compagnucci ), with latitudinal and altitudinal vegetation shifts in response to recurrent glacial oscillations (Quatrocchio et al . ).…”

Environmental and climatic proxies for the Cañadón Asfalto and Neuquén basins (Patagonia, Argentina): review of Middle to Upper Jurassic continental and near coastal sequences

“…Furthermore, in some levels of the La Matilde Formation, reptile footprints have been described (Casamiquela, 1964), expressing local (or generalized) arid conditions. Jurassic microfl oral similarities indicate close Gondwanic relations between Australia, India, and South America (Quattrocchio et al, 1996;Tiwari, 1999 Howell et al, 2005) showing the environment and vegetation from the Lajas Formation, Cuyo Group, Neuquén Basin (based on Martínez et al, 2008;Quattrocchio et al, 2011). Microcachryidites antarcticus is registered since the Lower Bajocian. Signifi cant increase in abundance of M. antarcticus and a corresponding decline of the Callialasporites 'complex' (C. dampieri, C. trilobatus, and C. microvelatus) were registered in the Tithonian (150.8-145.5 Ma) (Oppel Zone of Retitriletes watherooensis in Helby et al, 1987;Quattrocchio et al, 1996).…”