Upper Cretaceous macroflora from Sandwich Bluff Member, Vega Island, Antarctic Peninsula.

IGLESIAS A.; CARDENAS M. ; PIPO M.L.; O'GORMAN J.; CORIA R.A.

General Roca

Congreso; 11° Congreso de la Asociacion Paleontologica Argentina; 2016

Asociacion Paleontologica Argentina

A new late Maastritchian macroflora from the Sandwich Bluff Member (López de Bertodano Formation), located at Cape Lamb, Vega Island is communicated. The complete fossilbearing stratigraphical section is represented by a progradational near-shore marine environment. Although macrofloristic records are previous known, these were based only onbroad leaves assigned to Araucaria fibrosa Césari et al., 2009. Previous palynological analyses have also recorded Lycophytes, Cyateaceae, Osmundaceae, Polypodiaceae, Podocarpaceae, Proteaceae, Nothofagaceae, and several unidentified angiosperms. The small sample collected contains a well preserved new macroflora. A single pinna is assigned to thefern cf. Marattiopsis vodrazkae Kvacek, 2014 (Marattiaceae), formerly recorded for the earliest Campanian Hidden Lake Formation. Among angiosperms, four small-sized (nanophyll) and dentate leaf morphotypes were identified. The angiosperm leaves likely correspond to a new, unrecorded species for the James Ross Basin. A mature fossil cupule(woody flower involucre) consisting of four woody valves that are fused at their bases and partially preserve lamellae rows and cuticle, could be assigned to Nothofagaceae. This fossil encompasses the rich Nothofagaceae pollen record with three of the subgenera pollen-types from the late Campanian of the James Ross Basin (Snow Hill Island Formation). In summary, the new macroflora is in accordance with an important floristic change at the late Campanianearly Maastrichtian, which was supported by the palynological record of the Antarctic Peninsula. The floristic change can be associated to climatic shifting, although some plant families persist even into the Antarctic Paleogene temperate forests.