Preliminary studies of a new Eocene flora from King George Island, Antarctic Peninsula.

ARI IGLESIAS; FERNANDA CABRERA; ELIZABETH MOROSI; DANIEL PEREA; ANDREA CORONA; MARIANO VERDE; EVA M. SILVA; ANDRES BATISTA; FELIPE MONTENEGRO; PABLO TORIÑO

Buenos Aires

Congreso; Reunión Virtual de la Asociación Paleontológica Argentina RVCAPA, Argentina; 2020

Asociación Paleontológica Argentina

The Eocene continental sediments are well represented at the King George Island (25 de Mayo Island), South Shetland Islands, western Antarctic Peninsula. Plant fossils at the southern of the island are well known, and are related to the Fossil Hill Formation (FHF). Although there are several fossil outcrops at the Fildes Peninsula, most of the best preserved leaf compressions come from the lower member of FHF (lower-mid Eocene). The upper member (mid-upper Eocene) is less known, with few plant collections that are unpublished, preventing a detailed study of the floristic transition in Antarctica trough the greatest climatic change in the Cenozoic. Here we study a collection made by the Instituto Antártico Uruguayo in 2017 and curated in the Facultad de Ciencias repository (acronym FCDP-B); that come from an area near the Collins Glacier front. The fossiliferous section lithology is composed of yellowish-green tuffs interbedded with lava layers, and related to the FHF upper member. Leaves are relatively well preserved, with almost complete shape, and preserving the areolation and up to the  order veins. Until now, there were differentiated six leaf morphotypes, representatives of toothed angiosperms, small leaf conifers, and ferns. There were recognized familiar affinities to Atherospermataceae, Elaeocarpaceae, Nothofagaceae, and Podocarpaceae. The plant richness seems to be minor than the FHF lower member at the Fossil Hill site, but it may be blinded and related to undersampling bias.