Abstract presented at the 1999 ISAES Meeting in Wellington, New Zealand.

A.C. Ashworth,  Department of Geosciences, North Dakota State University, Fargo, ND 58105 USA
 ashworth@plains.nodak.edu
 

The Meyer Desert Formation outcrops in the Oliver Bluffs on the Beardmore Glacier, lat 85 deg. S, about 500 km from the South Pole.  Thin beds of siltstone with wood fragments, peat, and marl, are interbedded with diamictites.  The sediments are interpreted as fluvial and shallow lacustrine deposits that accumulated on the margins of a glacier. Plant fossils include wood, leaves and pollen of Nothofagus, seeds of vascular plants, and leaves and spores of several species of mosses.  The majority of the seeds appear to be those of a species of Ranunculus (Buttercup). There are also a few seeds that belong to Hippuris (Water Mare's Tail) and to Cyperaceae (Sedges).  Seeds previously attributed to Empetrum were probably misidentified.

  The insect chitin is represented by various parts of beetles including a head, several fragments of prothoraces, elytra, and legs.  One of the legs  still has setae preserved. Three species of beetles have been identified, two curculionids and possibly a helodid.  The curculionids are in the subtribe Listroderina.  The head has characteristics that indicate that it belongs to the Listroderes complex of southern South America but it is not closely  related to any extant taxa.  The prothoraces are from listroderines distantly related to the Falklandius/Tellurus group, also presently inhabiting the South Atlantic sector of the Southern Ocean.  In addition to the beetles, a large fly is represented by a puparium.  There are also large number of the immature stages of a lymnaeid gastropod and the broken valves of the Pea Clam, Pisidium. In addition to these aquatic species, there are a few ostracods, the tooth of a fish, and possibly the cases of caddis flies.

The weevil species indicates a biogeographic connection with South America but a distant one.  This supports the interpretation that the Meyer Desert biota evolved in isolation on Antarctica and was probably not reintroduced to Antarctica during a Neogene warm episode. The diversity of organisms represented by the Meyer Desert fossils implies a warmer climate than either the sparse pollen reported by Askin or the stressed tree rings in the contorted wood reported by Francis and Hill.  A glacial margin in Tierra del Fuego continues to be a potential modern analog for the Meyer Desert Formation.