Refining the chronology of Lujanian and Bonarian Stages

JOSÉ LUIS PRADO; DUVAL M; ADAMS, SH; FAVIER-DUBOIS, C.M; BELLINZONI, J.; BONINI, R.A.; MARIN-MONFORT, M.D.; TOMASSINI, R.L; GARCÍA-MORATO, S.; FERNÁNDEZ, FERNANDO JULIÁN; GÓMEZ, G.N.; STEFFAN, P. ; MONTALVO, C.I.; BAJKÁN, S.; SANTOS-ARÉVALO, F.J; BEILINSON, E; GASPARINI, G.M.; ALBERDI, M.T.; FERNÁNDEZ-JALVO, YOLANDA

Roma

Congreso; XXI INQUA Congress; 2023

INQUA

The late Pleistocene to Holocene sedimentary deposits in the Pampean Region of Argentina has traditionally been assigned to different stratotypes established more than a century ago by Ameghino (1879), the Lujanian, and Bonaerian. These Stages/Ages have been used as reference timescales for Argentina and other South American fossil sites. Nonetheless, there seems to be no consensus about the exact age and the litho- and biostratigraphic correlations of the Pleistocene units of the several sedimentary basins in the Chacopampean Plain geological province. This situation is also linked to the progressive change of geological time and its divisions, with the diversity of nomenclatures and the dual classification of deposits based on the content of fossils and lithological characteristics. In order to further chronologically constrain the transition between Lujanian and Bonaerian, we have recently employed Electron spin resonance (ESR), U-series, and Optically Stimulated Luminescence (OSL) methods to date and tentatively correlate a series of localities in different basins in the northern (San Pedro,) and southern (Salto de Piedra and Cascada de Paleolama) Buenos Aires Provinces. These preliminary results may be used to compare these two regions, different formations and timescale traditionally used in Argentina that will extend to other basins in the Chacopampean Plain geological province.