Continental Vertebrates During the Marine Isotope Stage 3 (MIS 3) in Argentina.

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

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

Springer

Año: 2016; p. 227 - 248

Paleontological sites in Argentina with continental vertebrates correspondingto the Marine Isotope Stage 3 (MIS 3) interval are scarce or poorly known.This situation is mainly due to the lack of absolute ages for Pleistocene fossil remainsor their bearing sediments that would allow the verification of the chronologyestablished for this interval. However, a few isolated evidences show that continentalvertebrates responded to the abrupt temperature changes that characterized the MIS 3(Heinrich colder events and Dansgaard?Oeschger warmer events). Up to date, continentalvertebrate remains of this age have been found mainly in Buenos Airesprovince, but also in a few sites of northeastern Argentina (such as Entre Ríos,Corrientes, Formosa and Chaco provinces). In Buenos Aires province: (1) Paso Otero,in the Río Quequén Grande valley, evidence of warmer and more humid conditionswere found in sediments dated in 37,800 ± 2300 radiocarbon years before present(RCYBP); (2) Mar del Sur, General Alvarado County, coastal marine sediments withcontinental mammals were dated in 25,700 ± 800 and 33,780 ± 1200 RCYBP;(3) Balneario Saldungaray, in the Río Sauce Grande valley, Tornquist County,gastropods associated with mammal remains were dated in 32,300 ± 1800 and27,500 ± 670 RCYBP; (4) Los Pozos, Marcos Paz County, sediments dated between29,000 and 33,000 RCYBP are associated with remains of mammals, birds, reptilesand amphibians; (5) San Pedro, San Pedro County, sediments bearing vertebrate faunahave two OSL datings of 37,626 ± 4198 and 41,554 ± 3756 years B.P. (YBP). InEntre Ríos province, Río Ensenada valley, Diamante Department, some levels of theTezanos Pinto Formation with OSL datings between 9000 and 35,000 YBP yieldedremains of grazer megamammals and other taxa characteristic of the modernPatagonian Domain. In the province of Corrientes, Arroyo Toropí, Bella Vista, vertebrateremains dated with OSL from 36,000 to 52,000 YBP show a clear taxonomicchange in response to climatic fluctuations. In Formosa province, Río Bermejo, VillaEscolar sediments of the Fortín Tres Pozos Formation, bearing vertebrate fauna havean OSL age of 58,160 ± 4390 YBP. In the province of Chaco, Charata locality,gastropods associated with mammal remains were dated between 22,000 and 27,000RCYBP. A larger amount of absolute datings of the bearing sediments and especiallytaxon dates are needed to determine more accurately the response of the fauna to theclimate changes characteristic of MIS 3.