El Chacay Fm - Rio Zeballos, Provincia de Santa Cruz (Miocene of Argentina)

Where: Argentina (46.9° S, 70.9° W: paleocoordinates 47.6° S, 65.2° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: El Chacay Formation, Burdigalian (20.4 - 16.0 Ma)

• STRATIGRAPHIC RELATIONS: From El Chacay Fm, which regionally overlies Basalto Posadas and is overlain by the Santa Cruz Fm (Eocene-Oligocene). THICKNESS: AGE: Eocene. No further detail provided. Justified on the basis of stratigraphic position and biostratigraphic correlation. This unit has more recently been dated as early Miocene (Burdigalian) by Sr isotopes (Cuitiño et al., 2015) and correlative units also as Burdigalian by U-Pb chronology (Cuitiño et al., 2012). STRATIGRAPHIC POSITION: Unknown stratigraphic position within section. Figure 3 (Chiesa et al. 1995) suggests that the collection is derived from multiple distinct beds within the formation at each section.

• group of beds-level stratigraphic resolution

Environment/lithology: marine; lithified sandstone and lithified, shelly/skeletal, sandy mixed carbonate-siliciclastic

• ENVIRONMENT: Shallow marine arenaceous platform, normal salinity, under a subtropical climate, with water temperatures between 19-22 degrees C.
• SPECIFIC LITHOLOGY: No specific lithology stated though Figure 3 (Chiesa et al. 1995) suggests that macrofauna are typically derived from sandstones and sandy coquinas at each section. LITHIFICATION: Lithified, based on figured specimens.

Size class: macrofossils

Collection methods: quarrying,

• COLLECTORS: Presumably collected by authors during broader lithostratigraphic study and geologic mapping (see Chiesa and Camacho, 1995). REPOSITORY: CIRGEO (Centro de Investigaciones en Recursos Geologicos), Argentina.

Primary reference: J.O. Chiesa, S.G. Parma, and H.H. Camacho. 1995. Observaciones estratigraficas en el Paleogeno del noroeste de la Provincia de Santa Cruz (Republica Argentina). Parte II: Invertebrados marinos de la Formacion El Chacy (Eoceno), Provincia de Santa Cruz, Argentina. Systematica y bioestratigrafia. Monografias de la Acadamia Nacional de Ciencias Exactas, Fisicas Y Naturales 11:17-68 [A. Hendy/A. Hendy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 65177: authorized by Austin Hendy, entered by Austin Hendy on 19.09.2006

Creative Commons license: CC BY (attribution)

Taxonomic list

• COVERAGE: Exhaustive for all macrofaunal groups (Brachiopoda, Bivalvia, Gastropoda). NOMENCLATURE: Authoritative paper using subgeneric and species-level designations.
Gastropoda
 Epitonioidea - Epitoniidae
 Neotaenioglossa - Calyptraeidae
Calyptraea juliana slipper shell
 Sorbeoconcha - Struthiolariidae
 Neogastropoda - Volutidae
Proscaphella santacrucensis Chiesa et al. 1995 volute
 Sorbeoconcha - Ficidae
"Ficus (Diconoficus) posadasensis" = Ficus posadasensis
"Ficus (Diconoficus) posadasensis" = Ficus posadasensis Chiesa et al. 1995 fig shell
Bivalvia
 Arcida - Arcidae
Anadara panensis Ihering 1914 ark
 Ostreida - Malleidae
Isognomon sp. Lightfoot 1786 oyster
 Carditida - Carditidae
Venericardia sp. Lamarck 1801 clam
Rhynchonellata
 Rhynchonellida - Notosariidae
 Terebratulida - Terebratellidae
Gmelinmagas plicata Marinelarena 1964
Echinoidea
 Clypeasteroida - Monophorasteridae
Iheringiella patagonensis Desor 1847 sand dollar