Reconstruction of eastern Pacific climate variability using multiple geochemical tracers in Cocos Island corals
Houston, Robb Eldon
Droxler, Andre W.
Master of Arts
Multiple isotopic and geochemical tracers were employed to unravel the complex history of recent environmental variability at Cocos Island. Downcore variations in delta18O, U/Ca, Sr/Ca, and Ba/Ca within coral skeletal aragonite correlate with environmental parameters such as temperature, precipitation, and advection of surface waters. U/Ca and Sr/Ca ratios were evaluated as potential paleothermometers in conjunction with delta 18O, and indicate a combined influence of temperature and precipitation on delta18O. Ba/Ca records indicate that this tracer may be a useful tracer for the advection of coastal waters from the Gulf of Panama and the strength of the NECC. Information regarding large-scale atmospheric and oceanic processes is also embedded within the records. Long-term trends are reproducible in coral records throughout the eastern Pacific and indicate significant changes in the tropical climate system. Records developed from Cocos Island suggest an increase in rainfall in conjunction with localized cooling during the past 100 years.
Geology; Environmental science; Geochemistry