Palynology of the Cañadón Asfalto Formation (Jurassic), Cerro Cóndor depocenter, Cañadón Asfalto Basin, Patagonia, Argentina. Paleoecology and paleoclimate based on ecogroup analysis

OLIVERA D.E.; ZAVATTIERI AM; QUATTROCCHIO MIRTA E.

PALYNOLOGY

AMER ASSOC STRATIGRAPHIC PALYNOLOGISTS FOUNDATION

Lugar: Dallas; Año: 2015

0191-6122

The Ca~nadon Asfalto Formation, Ca~nadon Asfalto Basin, Patagonia, Argentina, is interpreted as fluvial-lacustrinedeposits. A palynological study of the lower and middle parts of the unit, at the Ca~nadon Lahuinco and Ca~nadonCaracoles sections, Cerro Condor Depocentre Chubut province, northwestern Patagonia, Argentina is presented.The quantitative composition of the palynofloras is characterised by the dominance of pollen produced by theconifer families Cheirolepidiaceae (Classopollis) and Araucariaceae (mainly Araucariacites and Callialasporites),suggesting that warm-temperate and relatively humid conditions under highly seasonal climate prevailed during thedepositional times of the unit. The abundance of Botryococcus supports the presence of a shallow lake with probablysaline conditions. Five palynomorph ecogroups (PEGs) were recognised: upland, lowland, riverside, coastal lakeand aquatic. The ecological requirements of the different plant families forming the PEGs enable the inference of asub-tropical palaeoclimate for the Ca~nadon Asfalto region during late Early Jurassic to mid Middle Jurassic, whichis consistent with the ?seasonally dry (winterwet)? biome.Keywords: palynology; palaeoecology; palaeoclimate; Ca~nadon Asfalto Formation; Patagonia; Early to MiddleJurassic; Argentina