INVESTIGADORES
OLIVERO Eduardo Bernardo
congresos y reuniones científicas
Título:
Carbonate isotope chemostratigraphy of the late Cretaceous - early Tertiary from Seymour Island, Antarctica
Autor/es:
TOBIN, T.; WARD, P.; OLIVERO, E. B.; KIRSCHVINK, J.; PASSEY, B.
Lugar:
Portland, USA
Reunión:
Conferencia; 2009 Portland Geological Society of America Meeting, October 18-21 2009.; 2009
Institución organizadora:
Geological Society of America
Resumen:
Seymour Island, in the James Ross Basin on the West Antarctic Peninsula, is the southernmost marine K-T boundary
section in the world, and consequently provides valuable information on the latitudinal variability on the impact of the KT
event. Seymour Island has moved less than three degrees of latitude since deposition and has undergone minimal
deformation (structural tilt ~5°) and diagenesis (most fossils preserve original aragonite). The Lopez de Bertodano
formation is comprised of immature mud to sand deposited in a back-arc setting on the middle to inner shelf during the
upper Maastrichtian and Danian. Carbon isotopic data is currently being generated from both aragonitic shell material
and bulk rock samples to create a detailed chemostratigraphy. Recent identification of the magnetic chrons 31R/31N
and 30N/29R on Seymour Island during ongoing paleomagnetic analysis at Caltech provides a firm basis for correlation
with other K-T sections around the world as well as firm tie points for chemostratigraphy. Preliminary ä18O data from
aragonitic (confirmed by XRD analysis) shells suggest that temperatures were considerably higher during the
Maastrichtian and Danian than today (~10°C versus near 0°C), assuming minimal diagenetic alteration and a seawaterä18O data from
aragonitic (confirmed by XRD analysis) shells suggest that temperatures were considerably higher during the
Maastrichtian and Danian than today (~10°C versus near 0°C), assuming minimal diagenetic alteration and a seawater
ä18O composition of -1.0. These results are in broad agreement with previous studies and with preliminary results
using the clumped isotope in carbonate paleothermometer, which indicate seawater temperatures of ~12°C or lower.18O composition of -1.0. These results are in broad agreement with previous studies and with preliminary results
using the clumped isotope in carbonate paleothermometer, which indicate seawater temperatures of ~12°C or lower.