Paso del Halcon "Level #1" (Pliocene of Argentina)

Also known as Ca. 13 km upstream from the mouth of the Quequén Salado

Where: Buenos Aires, Argentina (38.8° S, 60.5° W: paleocoordinates 38.9° S, 59.4° W)

• coordinate stated in text

• small collection-level geographic resolution

When: Irene Formation, Zanclean (5.3 - 3.6 Ma)

• Prevosti et al. 2021: On analysis, one aliquot of a sample from QSLo (lower Quequén Salado, Paso del Halcón) presented extensive evidence of excess argon in the first half of the spectrum, but the final steps representing about 50% of released 39Ar yielded an age of 5.17 ± 0.08 Ma. Our results close almost a century of argument concerning the relative antiquity of the “Irenean” (Kraglievich 1934, Goin et al. 1994, Pardiñas et al. 2017, Beilinson et al. 2017). The controversial lower fauna from the Quequén Salado River can now be shown to be of Zanclean age (5.17 Ma) and thus well within the Early Pliocene.

Environment/lithology: terrestrial; brown, red siltstone

• A basal level #1 is mostly composed of very hard dark reddish-brown loessoid silt plenty of calcrete nodules, and much less frequent crotovines filled with more friable sediments (Fig. 7). An overlying level #2 is of yellowish-brown sandy silt with calcrete concretions and diamicton facies to the top, where a calcrete crust is partially developed. The cuspidal level #3 is of pinkish-brown to reddish-brown loessoid silts with silt fragments embebed, crotovines and, also, ichnological evidence of vespid and scarabeid nests- and diamicton deposits. The upper limit of this latter layer is cut by younger sediments (Fig. 5).

Size class: macrofossils

Reposited in the MLP

Primary reference: U. F. J. Pardinas, F. J. Prevosti, D. Voglino and M. Cenizo. 2017. A controversial unit within the argentine neogene: the “Irenean” fauna. Ameghiniana 54(6):655-680 [E. Vlachos/E. Vlachos]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 191774: authorized by Evangelos Vlachos, entered by Evangelos Vlachos on 14.02.2018, edited by Kateryn Pino

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Mammalia
 Notoungulata - Hegetotheriidae
Paedotherium minor
Paedotherium minor Cabrera 1937 notoungulate
 Rodentia - Chinchillidae
Lagostomus euplasius
Lagostomus euplasius Ameghino 1908 viscacha
 Cingulata - Dasypodidae
Macrochorobates sp., Doellotatus inornatus
Macrochorobates sp. Scillato Yané 1980 armadillo
Doellotatus inornatus Rovereto 1914 armadillo