INVESTIGADORES
FIORELLI lucas Ernesto
congresos y reuniones científicas
Título:
PRELIMINARY CLUMPED ISOTOPE DATA FROM LATE CRETACEOUS TITANOSAUR (SAUROPODA) EGGSHELLS: PRESERVATION OF THE ORIGINAL ISOTOPIC SIGNAL AND IMPLICATIONS FOR PALAEOECOLOGICAL AND PALAEOBIOLOGICAL INTERPRETATIONS
Autor/es:
LEA LEUZINGER; STEFANO BERNASCONI; LUCAS ERNESTO FIORELLI; MARTÍN HECHENLEITNER; PABLO ALASINO
Lugar:
Caparica, Lisboa
Reunión:
Simposio; VI Symposium on dinosaur eggs and babies; 2017
Institución organizadora:
Universidade Nova de Lisboa
Resumen:
For several decades, scientists have relied on stable isotope analyses on fossils andassociated sediments for palaeoecological and palaeoenvironmental reconstructions.The fractionation of oxygen and carbon isotopes between a mineral and the originalfluid it precipitated from depends on temperature. Information related to climate,environment and/or physiology can thus be inferred from the isotopic composition ofboth, the mineral and original fluid, by means of established fractionation equations.The most limiting factor of this method is that the isotopic composition of the originalfluid (e.g. meteoric water, body water, marine water) is unknown for geological andfossil samples and must consequently be estimated.A recently developed stable isotope method called ?carbonate clumped isotopethermometry? now allows to calculate the precipitation temperature of a mineralindependently of the isotopic composition of its original fluid, basing only on theabundance of 13C-18O bonds within a carbonate molecule, which is temperaturedependant.When applied on fossils (eggshells, carbonate fraction in tooth apatite?),clumped isotope analyses give direct information on the body temperature of theanimal, provided that the primary isotopic composition is preserved.We ran classical oxygen and carbon, as well as clumped isotope analyses onLate Cretaceous dinosaur eggshells, associated pedogenic carbonate nodulesand hydrothermal crystals from three different titanosaur nesting sites of La Riojaprovince, NW Argentina. The results show that the eggshells of two sites areisotopically poorly preserved, meaning that the calculated precipitation temperature(>40°C) most probably corresponds to that of secondary calcite. However, theeggshells of the third one show values different from associated, diageneticcarbonate and can thus be used to answer palaeophysiological questions. Wewill provide preliminary information on body temperature of titanosaurs and on theenvironmental conditions that prevailed in these three study sites, likely ideal fornesting.