A Fossil Wood Flora from King George Island: Ecological Implications for an Antarctic Eocene Vegetation

Early Tertiary sediments of the Antarctic Peninsula region continueto yield a rich assemblage of well-preserved fossil dicotyledonousangiosperm wood. The wood flora under consideration is fromthe Collins Glacier region on Fildes Peninsula, King GeorgeIsland and is derived from tuffaceous sediments of the MiddleUnit of the Fildes Formation. These deposits accumulated ina volcanic setting adjacent to a basic-intermediate stratocone.The fossil assemblage provides further evidence for the existenceof cool temperate forests, similar in composition to those foundtoday in New Zealand, Australia and, in particular, southernSouth America. This paper describes two conifer and five angiospermmorphotypes, four of which are new additions to the Antarcticapalaeoflora records. Cupressinoxylon Goeppert, which is thedominant conifer in terms of numbers, and Podocarpoxylon Gothanrepresent the conifers. The angiosperm component includes twospecies ofNothofagoxylon and two previously undescribed woodmorphotypes that exhibit greatest anatomical similarity to woodsofLuma A. Gray (Myrtaceae) and Eucryphia Cav. (Cunoniaceae).These morphotypes are described and assigned to the organ generaMyrceugenelloxylon Nishida, and Weinmannioxylon Petriella, respectively.A model based on the extant cool temperate Valdivian rainforestsis proposed and ecological reconstructions based on palaeobotanicaland geological evidence suggest that changes in the palaeovegetationreflect natural dynamics following volcanic disturbances.Copyright2001 Annals of Botany Company Fossil wood, Antarctica, Myrtaceae, Eucryphia, Nothofagaceae, Eocene, Valdivia, Tertiary