See more from this Division: Gulf Coast Association of Geological Societies
See more from this Session: Applied Micropaleontology: Tools and Techniques for the 21st Century
Abstract:
Correlation analysis indicates that the absolute abundance of total radiolarians (AAT, for 38 samples to date) in the dataset is negatively correlated with δ18O values of the samples at the 5% significance level. Furthermore, this correlation is mainly due to the significant (at the 2% level) negative correlation between the absolute abundance of sphaerellarians and the δ18O values. There is a less well developed correlation (significant at the 10% level) between the AAT and the δ13Ccarb values. Since carbonate δ18O values are lighter in freshwater than in seawater, a negative excursion of δ18O may represent a decline of paleosalinity through increased riverine input. Hence, these correlations may indicate that sphaerellarians are more sensitive to salinity changes than Follicucullus, and are more prosperous at lower salinities. However, due to the various perturbing factors on oxygen isotope values of old rocks, other potential proxies for paleosalinity such as Sr/Ca, Mg/Ca, and Ba/Ca will be analyzed in relationship to the radiolarian shifts in order to further test this hypothesis.
See more from this Division: Gulf Coast Association of Geological Societies
See more from this Session: Applied Micropaleontology: Tools and Techniques for the 21st Century