El Durazno 21, Agrio Formation (Cretaceous of Argentina)

Where: Argentina (37.8° S, 70.4° W: paleocoordinates 36.9° S, 33.5° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Agrio Formation, Late/Upper Valanginian (140.2 - 136.4 Ma)

• approx. 140 m above the base of the formation

• bed-level stratigraphic resolution

Environment/lithology: marine; concretionary, black, silty, calcareous shale and shelly/skeletal, calcareous packstone

• dark (varying shades of grey, black and green) silty shales containing calcareous nodules and interbedded calcareous coquina and at the base, medium-grained sandstones, this unit is a "black shale"

Size class: macrofossils

Primary reference: M. B. Aguirre-Urreta and P. F. Rawson. 1999. Lower Cretaceous ammonites from the Neuquen Basin, Argentina: Viluceras, a new Valanginian subgenus of Olcostephanus. Cretaceous Research 20:343-357 [J. Alroy/E. Leckey/M. Clapham]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 37776: authorized by John Alroy, entered by Erin Leckey on 23.03.2004

Creative Commons license: CC BY (attribution)

Taxonomic list