Seymour Island (Institute of Polar Studies location 15): Bartonian, Antarctica

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Cephalopoda - Nautilida - Aturiidae
Aturia sp. Bronn 1838
see common names

Geography
Country:Antarctica
Coordinates: 64.2° South, 56.7° West (view map)
Paleocoordinates:64.0° South, 59.7° West
Basis of coordinate:based on nearby landmark
Geographic resolution:outcrop
Time
Period:Paleogene Epoch:Eocene
Stage:Bartonian 10 m.y. bin:Cenozoic 3
Key time interval:Bartonian
Age range of interval:41.20000 - 37.71000 m.y. ago
Stratigraphy
Formation:La Meseta
Stratigraphic resolution:bed
Stratigraphy comments: From middle part of Unit II of Elliot & Trautman. Equivalent to lower-middle part of Telm 5. The age model for the La Meseta Formation (and recently-defined Submeseta Formation) is controversial. Strontium isotopes (Ivany et al., 2008) suggest earlier ages, with the La Meseta (Telm1-Telm5) almost entirely Ypresian and the Submeseta (Telm6-Telm7) Middle-Late Eocene. Montes et al. (2013) also created an age model incorporating magnetostratigraphy to support the largely-Ypresian age for the La Meseta and Middle-Late Eocene for the Submeseta. Some mammals are similar to the radiometrically-constrained late early Eocene Paso del Sapo assemblage of Patagonia (Gelfo et al., 2009, Tejedor et al., 2009), but the mammals are not exactly similar (Bond et al., 2011). However, Douglas et al. (2014) re-evaluated the strontium data and used dinoflagellate biostratigraphy to argue for a Lutetian (Telm2-4) and younger (Bartonian to mid-Priabonian for Telm5-6) age range. Amenábar et al. (2019) also found younger ages from dinoflagellates: Lutetian (Telm1-mid Telm 3), Bartonian (mid Telm 3-mid Telm 5), and Priabonian (upper Telm 5), SPDZ10-SPDZ13. This age range is more consistent with the presence of basilosaurid whales in Telm4 and Telm7, as basilosaurids are globally-distributed first in the middle Eocene (Buono et al., 2016). Although the ages are still debated, the dinoflagellate age model of Amenábar et al. (2019) is used here.
Lithology and environment
Primary lithology: "siliciclastic"
Environment:paralic indet.
Geology comments: The environment of deposition of this complex unit has been subject to different interpretations, all agreeing in general that Telm5 represents a shallow-marine setting. A study by Wiedman and Feldmann (1988) on the ichnofossil fauna and depositional environment of the La Meseta Formation concluded that the Telm5 setting was a littoral to very shallow sublittoral clastic marine terrain, definitely above storm base and most probably above normal wave base. They agreed with Elliot and Trautrnan (1982) that Units II and III probably represent a tidally dominated environment, but evidence from sedimentary structures is also consistent with a barrier bar model and does not represent a shallowing upward sequence. Elliot and Trautman (1982) favored a deltaic model. The analysis of trace fossils and body fossils (including vertebrate remains and large, abundant wood fragments) indicates variable nearshore, shallow-marine environments. A scenario for the depositional environment could include a combination ebb-tidal (or possibly flood-tidal) delta-barrier island complex (Stilwell & Zinsmeister, 1992).
Taphonomy
Modes of preservation:cast
Size of fossils:macrofossils
Collection methods and comments
Reason for describing collection:general faunal/floral analysis
Collection method comments: Repository: probably Ohio State University
Metadata
Database number:180151
Authorizer:M. Clapham Enterer:M. Clapham
Modifier:M. Clapham Research group:marine invertebrate
Created:2016-07-09 23:33:42 Last modified:2019-08-18 00:15:42
Access level:the public Released:2016-07-09 23:33:42
Creative Commons license:CC BY
Reference information

Primary reference:
59803. W. J. Zinsmeister. 1978. Eocene nautiloid fauna from the La Meseta Formation of Seymour Island, Antarctic Peninsula. Antarctic Journal of the United States 13(4):24-25 [M. Clapham/M. Clapham]