Also known as CH1

Where: Río Negro, Argentina (41.4° S, 69.6° W: paleocoordinates 43.6° S, 60.7° W)

• coordinate stated in text

• small collection-level geographic resolution

When: Lower Member (Las Chacras Formation), Bartonian to Bartonian (41.3 - 33.9 Ma)

• The strong similarity with the Mustersan assemblage from the Rosado Member at Gran Barranca South of Colhué Huapi Lake, with a well constrained age of 38.16 – 37.4 Ma. (Dunn et al., 2013), suggests that the Lower Las Chacras Formation and its fauna is more likely of late Bartonian or early Priabonian age. Fossils come from 45 m above the base and 3 m below the major pyroclastic flow of the upper half of the measured section.

• bed-level stratigraphic resolution

Environment/lithology: fluvial; conglomerate

Size class: macrofossils

Collection methods: Collected by Rodolfo Casamiquela during 1940’s and 1950’s. Further collection by Kramarz et al. 2022 in October 2017 and April 2018

Primary reference: A. Kramarz, E. Bellosi, M. Bond, A. M. Forasiepi, J. C. Fernicola, G. Aguirrezabala, and D. T. Rezende. 2022. Eocene mammals from volcaniclastic deposits of the Somun Cura Plateau: biostratigraphic implications for north Patagonia Paleogene. Andean Geology 49(2) [P. Mannion/G. Varnham/P. Mannion]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 225620: authorized by Philip Mannion, entered by Grace Varnham on 20.05.2022

Creative Commons license: CC BY (attribution)