Continental vertebrates during the marine isotope stage 3 (MIS 3) in Argentina.

DESCHAMPS, C.M.,; SOIBELZON, L.H.; SOIBELZON, E.; BEILINSON, E.; GASPARINI, G.M.; FRANCIA, A.; TONNI, E.P.

Marine Isotope Stage 3 in Southern South America 60 ka B.P.-30 ka B.P.

Springer

Año: 2016; p. 227 - 247

Paleontological sites in Argentina with continentalvertebrates corresponding to the Marine Isotope Stage 3 (MIS3) interval arescarce or poorly known. This situation is mainly due to the lack of absoluteages for Pleistocene fossil remains or their bearing sediments that would allowthe verification of the chronology established for this interval. However, afew isolated evidences show that continental vertebrates responded to theabrupt temperature changes that characterized the MIS3 (Heinrich colder eventsand Dansgaard-Oeschger warmer events). Up to date, continental vertebrateremains of this age have been found mainly in Buenos Aires province, but alsoin a few sites of northeastern Argentina (such as Entre Ríos, Corrientes,Formosa and Chaco provinces). In Buenos Aires province: (1) Paso Otero, in the RíoQuequén Grande valley, evidence of warmer and more humid conditions were foundin sediments dated in 37,800 ± 2,300 radiocarbon years before present (RCYBP); (2)Mar del Sur, General Alvarado County, coastal marine sediments with continentalmammals were dated in 25,700+/- 800 and 33,780+/-1,200RCYBP; (3) Balneario Saldungaray, in the Río SauceGrande valley, Tornquist County, gastropods associated with mammal remains weredated in 32,300 +/- 1,800 and 27,500+/- 670 RCYBP; (4) Los Pozos, MarcosPaz County, sediments dated between 29,000 and 33,000 RCYBP are associated withremains of mammals, birds, reptiles and amphibians; (5) San Pedro, San PedroCounty, sediments bearing vertebrate fauna have two OSL datings of 37,626 ± 4,198 and 41,554 ± 3,756years B.P. (YBP). In Entre Ríosprovince, Río Ensenada valley, Diamante Department, some levels of the TezanosPinto Formation with OSL datings between 9,000 and 35,000 YBP yielded remainsof grazer megamammals and other taxa characteristic of the modern PatagonianDomain. In the province of Corrientes, Arroyo Toropí,Bella Vista, vertebrate remains dated with OSL from 36,000 to 52,000 YBP show aclear taxonomic change in response to climatic fluctuations. In Formosa province,Río Bermejo, Villa Escolar sediments of the Fortín Tres Pozos Formation, bearingvertebrate fauna have an OSL age of 58,160 +/-4,390 YBP. In the province of Chaco,Charata locality, gastropods associated withmammal remains were dated between 22,000 and 27,000 RCYBP. A largeramount of absolute datings of the bearing sediments and especially taxon dates areneeded to determine more accurately the response of the fauna to the climatechanges characteristic of MIS3.