Paleocene-Eocene vegetation and early grass ecology in the San Jorge Basin of Argentine Patagonia

ELENA STILES; CAROLINE A.E. STRÖMBERG; GEORGINA ERRA; JAVIER GELFO; FRANCISCO GOIN

Seattle

Encuentro; 37th Midcontinent paleobotanical colloquium 2020; 2020

University of Washington and the Burke Museum

Modern grasses in the family Poaceae exhibit exceptional taxonomic and ecological diversity, with grassland-dominated habitats covering about 40% of Earth?s land surface. Grasslands today occur in a range of temperate to tropical ecosystems, spanning low to high altitudes and wet to arid climates. However, because of the scant fossil record of grasses before the global Oligocene-Miocene spread of grasslands, the ecology of early grasses and their environmental affinities remain poorly understood. To address this gap, we analyze phytolith assemblages extracted from sediment samples collected at the Estancia Las Violetas locality to reconstruct the vegetation of the late Paleocene - early Eocene Rio Chico Group in the San Jorge Basin of Argentine Patagonia. The coastal lowland deposits of the Las Violetas and Las Flores formations of the Rio Chico Group, dated from 57.9±1.1 Ma to