Calcareous nicrofossils (Ostracoda and Foraminifera) from the MIS 1 at the Salado basin (Arroyo San Miguel site, Pila, Buenos Aires Province, Argentina

RAMOS, N.; CARIGNANO, A. P.; CUSMINSKY, G.; FUCKS, E.

Advances in South American Micropaleontology - Selected papers of the 11th Argentine Paleontological Congress. Springer Earth System Sciences

Springer International Publishing

Año: 2019; p. 159 - 174

A unit of 30 cm thick attributable to the Marine Isotopic Stage 1 (MIS 1) (Canal de Las Escobas Formation) was identified at the study site, between the Members Gorch and Puente Las Gaviotas of the Luján Formation. The ostracods Cyprideis salebrosa hartmanni Ramírez, Leptocythere sp., Cytherura dimorphica Bertels and Martínez, Limnocythere cusminskyae Ramón-Mercau, Plastani and Laprida, L. solum (Whatley and Cholich), L. multiperforata (Whatley and Cholich), and the foraminifers Ammonia tepida (Cushman), A. parkinsoniana (d?Orbigny) and Elphidium gunteri (Cole) where recognized. The ostracods recovered include common species of estuarine environments and with wide salinity tolerance. The Ammonia-Elphidium association is also typical of oligo-mesohaline conditions. This low diversity association, with clear dominance of C. salebrosa hartmanni, plus the presence of C. dimorphica, Leptocythere sp. and the Foraminifera mentioned above, is indicative of environments with marine influence. Moreover, a wedge of sediments containing shells of the bivalve Anomalocardia brasiliana (Gmelin), was dated obtained a radiocarbon age of 5580 ± 110 years BP (6278?6511 cal. years BP). This information suggests that Arroyo San Miguel site represents the most internal locality assignable to the MIS 1 marine transgression.