PALEONTOLOGICAL RECORD OF A GONDWANA CRETACEOUS PALEOLAKE AS PROXY FOR PALEOCLIMATE RECONSTRUCTION

The La Cantera Formation (Aptian) represents an underfilled lake system developed in extensional basin during the Cretaceous hothouse and it bears abundant diverse fossil record. Our goal was to investigate paleoclimate conditions of unit from a multiproxy approach. We analyzed two proxies: a) stable isotope (carbon oxygen) composition basal Actinopterygii Neopterygii fish remains indeterminate plant remains; b) clay mineral assemblage composition; providing independent lines evidence reconstruct including paleotemperature calculations for waters. values obtained δ13C range between -8.4 -1.3 ‰ (δ13C= χ -5.57‰; σ ± 2.25); δ18O that vary -5.7 -3.6‰ (δ18O= -4.33‰; 0.84); case -25.8 -22.8‰ -25‰ -4.33). Paleotemperatures water column ranged 23.33 35.80 °C. Plant signature allowed obtaining δ13CCO2 -5 ‰. This agrees with interpretation originating sediment deposition global climate context Cretaceous. is dominated by illite-smectite indicating enhanced hydrolysis seasonal rainfall supporting temporal warmup lake. data supports aridity paleolake existence. These findings suggest geochemical proxies paleontological datasets are accurate reconstructions deep time records lacustrine system.