Where: Mendoza, Argentina (35.0° S, 68.5° W: paleocoordinates 35.5° S, 64.4° W)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Aisol Formation, Colloncuran (15.5 - 13.8 Ma)

• This collection had a M. Miocene, Santacrucian age assigned. But:

•

•In preliminary studies, the Aisol Formation was considered early Miocene (probably Santacrucian SALMA; e.g., Groeber 1951; Dessanti 1954, 1956; González Díaz 1972; Núñez 1976) based upon few fossil findings and stratigraphic correlations. Nonetheless, it is also worth mentioning that in one of those preliminary studies, Groeber (1952) suggested that the unit (informally called «Estratos Calchaquíes» by then) was late Miocene, and was included among the «Arauco-Entrerriano» levels. Later studies did not further the debate. Pascual and Odreman-Rivas (1973; see also Pascual and De la Fuente 1993) placed the Aisol Formation in the Miocene, in the temporal interval between the Santacrucian and Friasian SALMAs. It was after the analysis of new fossil findings that Soria (1983) specifically allocated the Aisol Formation to the Friasian s.l. (including Colloncuran, Friasian s.s., and Mayoan, following Bondesio et al. 1980), because of the occurrence of post-Santacrucian and pre- Chasicoan mammals. This hypothesis was also followed by later authors (Sepúlveda et al. 2001, 2007). The analysis of the new fossil material and the strati- graphic control of the findings led to recognize two dif- ferent fosiliferous sections in the profile, with faunal as- semblages of different ages. The LS is probably middle Miocene, as Soria suggested (1983), perhaps Friasian s.s. (older than 15 Ma; Marshall and Salinas 1990) or Colloncuran (15.5-14 Ma; Marshall et al. 1977; Marshall and Salinas 1990), following the Patagonian scheme. Unfor- tunately, there is no consensus about the time span cov- ered by some of the SALMAs, including the Friasian one. Specific studies on age and taxonomic composition are needed before making any comparisons with more distantly located stratigraphic units.

•Three different sections are recognized within the Aisol Formation, with fossil vertebrates in the lower (LS) and middle (MS) sections. According to preliminary results of Forasiepi et al., 2011: Lower Section: Friasian s.s (not used anymore). or Colloncuran and Middle Section: Huayquerian.

Environment/lithology: terrestrial; lithology not reported

Size class: macrofossils

Collected by Soria; Gonzales Díaz, E. Núnez in 1979; reposited in the MACN, MLP

Primary reference: M. F. Soria. 1983. Vertebrados fósiles y edad de la Formación Aisol, Provincia de Mendoza. Revista de la Asociación Geológica Argentina 38(3-4):299-306 [C. Jaramillo/J. Carrillo]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 145811: authorized by Carlos Jaramillo, entered by Juan Carrillo on 11.06.2013

Creative Commons license: CC BY (attribution)