Conifer Fossil Woods from the Sobral Formation (Lower Paleocene, Western Antarctica)

Abstract

Conifer fossil woods represent 54% of an assemblage of 116 specimens collected from sediments of the Sobral Formation in Seymour (Marambio) Island, Western Antarctica. These woods are anatomically described in detail and assigned to seven fossil-species of the following fossil-genera: Agathoxylon (Araucariaceae), Podocarpoxylon, Phyllocladoxylon, Protophyllocladoxylon (Podocarpaceae), and Cupressinoxylon (Podocarpaceae/Cupressaceae). The conifer wood assemblage reveals that the most common woods are those of Agathoxylon, therefore indicating a relative abundance of the Araucariaceae in the Antarctic Paleocene forests. This abundance of the Araucariaceae woods is locally continued in the overlying Cross Valley Formation (Paleocene). Podocarpaceae woods are found in almost similar proportions to those of the Araucariaceae. Almost the other half of the fossil woods are dicotyledon woods. The proportions of the identified fossil wood taxa are consistent with those of the palynological studies of the same stratigraphic unit.