RECONSTRUCCIONES PALEOCLIMÁTICAS EN CALCRETAS NORDPATAGÓNICAS UTILIZANDO LAS COMPOSICIONES ISOTÓPICAS 18O DEL AGUA DE PRECIPITACIÓN

BOUZA, PABLO; BISIGATO, ALEJANDRO; DAPEÑA, CRISTINA

Mar del Plata

Otro; III Reunión Argentina de Geoquímica de la Superficie; 2014

UNMDP- IIMYC (CONICET), Inst Geol de Costas y Cuaternario

The objective of this work is to estimate paleotemperatures from δ18O composition of pedogenic carbonates (cp) in paleosols from NE of Chubut, combining the equation that describes temperature-dependent fractionation of oxygen between water and calcite with spatial (IAEA / WMO database) and temporal (Puerto Madryn station) relationships between temperature and δ18O of water precipitation (p). On the other hand, paleotemperatures were estimated by δ18Ocp-TMA relationships from modern pedogenic carbonate. Fifteen soil profiles were studied; eleven in the Rodados Patagónicos and four in marine terraces of Caleta Valdés Formation. As the lapse of carbonate formation is during the warmer period, the temporal δ18Op?temperature relationships of summer months were used. The summer mean temperature varied between 20 and 27 ºC. The slope of this relationship is similar to those obtained by spatial relationships, giving a TMA-TMMV difference between 12 and 13 ºC. We conclude that δ18Op-TMA relations can be used to assess climate changes during interglacial periods of pedogenic carbonate formation