RECONSTRUCTION OF MIDDLE PLEISTOCENE – HOLOCENE CLIMATE OF S.JORGE GULF (PATAGONIA, ARGENTINA) USING MARINE MOLLUSCS: PRELIMINARY GEOCHEMICAL DATA

CONSOLONI I., BANESCHI I., ZANCHETTA G., AGUIRRE M.L., BINI M., BORETTO G.M., DALLAI L., FUCKS E., GUIDI M., , ISOLA I., PAPPALARDO M., RAGAINI L., RIBOLINI A.

Montecarlo

Simposio; IAEA International Symposium on Isotopes in Hydrology, Marine Ecosystems, and Climate Change Studies; 2011

Patagonia is an unique region of the world because it is the only continental landmass emerging along mid to low-latitudes in the Southern Hemisphere. The Quaternary coastal deposits of Atlantic Patagonia are often organized in spectacular successions of raised beach-ridges deposits. Beach ridges often contain a great amount of fossils. Although paleontological studies have been conducted in the recent past, there are not practically geochemical studies on these natural archives to infer local paleoceanographic and paleoclimate changes. Preliminary geochemical studies (stable isotopes and trace elements) on the aragonitic shell Protothaca antiqua collected in various localities from Holocene to Middle Pleistocene (MIS 1 to MIS 11) indicate that isotopic composition of different set of beach ridges contains characteristic stable isotope composition, which can be preliminarily interpreted as different salinity and temperature conditions. These differences seem maintained by trace elements data, suggesting that water geochemistry was affected too.