Oliver Bluffs (Miocene of Antarctica)

Where: Antarctica (85.1° S, 166.7° E: paleocoordinates 86.1° S, 156.0° E)

• coordinate stated in text

• outcrop-level geographic resolution

When: Meyer Desert Formation (Sirius Group), Middle Miocene (16.0 - 11.6 Ma)

• Based on the occurrence of marine diatoms within the Sirius Group deposits, their age was reported as Pliocene c. 3 Ma (Webb et al. 1994). This age estimate, however, is controversial and likely too young. Several studies suggest that the diatoms were deposited onto older glacial deposits by wind from Pliocene marine deposits located on the margins of the continent (Scherer et al. 2015). Pollen from the Meyer Desert Formation most closely matches an assemblage from near Mount Boreas in the McMurdo Dry Valleys dated by 39Ar/40Ar from a volcanic ash to be of mid-Miocene age (14.07 ± 0.05 Ma., Lewis et al. 2008). Also, fossiliferous Neogene deposits in the region of the Friis Hills in the McMurdo Dry Valleys are early to mid-Miocene based on 39Ar/40Ar dating (Lewis and Ashworth 2016). We conclude that the best age estimate for the trechine fossils is mid-Miocene.

Environment/lithology: fine channel fill; lithified siltstone and fine-grained sandstone

• The siltstone lens formed from the infilling of a stream channel. Insect and plant parts were washed or blown into the stream channel which eventually became sediment-choked and finally buried by lodgement till during the next glacial advance down the valley.
• The fossiliferous siltstones and fine sandstones are cemented with calcite.

Size class: mesofossils

Preservation: replaced with calcite

Reposited in the USNM

• They were disaggregated by soaking in water and wet sieving. The fraction greater than 300 um was examined under a binocular microscope. The fossils are mounted on card slides and are stored in the collections of the Quaternary Entomology Laboratory at North Dakota State University.

Primary reference: A. C. Ashworth and G. Kuschel. 2003. Fossil weevils (Coleoptera: Curculionidae) from latitude 85˚S Antarctica. Palaeogeography, Palaeoclimatology, Palaeoecology 191:191-202 [M. Clapham/J. Karr/P. Wagner]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 137622: authorized by Matthew Clapham, entered by Jered Karr on 18.12.2012, edited by Matthew Clapham

Creative Commons license: CC BY (attribution)

Taxonomic list

 Coleoptera - Curculionidae
"Listroderina "indet 1"" = Listroderini, "Listroderina "indet 2"" = Listroderini
"Listroderina "indet 1"" = Listroderini Le Conte 1876 snout beetle
similar to those of the Listroderes complex.
"Listroderina "indet 2"" = Listroderini Le Conte 1876 snout beetle
 Coleoptera - Carabidae
Antarctotrechus balli n. gen. n. sp.1
Antarctotrechus balli n. gen. n. sp.1 Ashworth and Erwin 2016 ground beetle
NMNH:ADP147741, NMNH:ADP147732
 Diptera -
Schizophora indet.2 Becher 1882 fly