Cretaceous climatic reconstruction from Argentina based on palynological data / Reconstrucción climática del Cretácico de Argentina basado en datos palinológicos

PAULA L. NARVAEZ; MERCEDES B. PRÁMPARO; BARBARA VENTO; NATALIA MEGO; GRISELDA G.PUEBLA

BOLETIN GEOLOGICO Y MINERO

Instituto Geologico y Minero de España

Lugar: Madrid; Año: 2018 p. 615 - 631

0366-0176

Paleoclimatic reconstructions have used different proxies as climateindicators. In this context, palynomorphs play a crucial role for makinginferences about past climate changes because of their presence anddistribution during the geologic history in almost all type of environments.Argentina has a wide latitudinal range in South America, with diverse cretaceousunits yielding palynomorphs that represent different climatic conditions.Cretaceous was a time when climatic conditions showed some special variations.Different theories about the climatic conditions at this time were postulated.The main aim of this contribution is to understand climatic trends during theCretaceous, based on the quantitative analysis of selected pollen and spores,considered as climate indicators, from different geological units in Argentina.The evaluation of the palynofloras has been undertaken mainly by reviewingpublished sources from cretaceous basins but also with our own unpublisheddata. The climatic trend during the Cretaceous showed that the Early Cretaceousis marked by aridity episodes with high values of Classopollis and Gnetales. In contrast, the Late Cretaceous showedwarm and more humid conditions indicated by increasing values of free-sporingplants (especially Bryophytes and ferns) and palm pollen grains, and thedecrease until absence of the aridity indicators.