Geochemical Tools and Paleoclimate Clues: Multi-Molecular and Isotopic Investigations of Tropical Marine Sediments and Alpine Ice

摘要

South American climate has undergone dramatic changes since the last glacial period, as evidenced from Cariaco Basin (Venezuelan coast) and Peru Margin marine sediment biomarker records. Compounds derived from vascular plant leaf waxes and delivered to the marine sedimentary environment, including long- chain (C24-C32) n alkanoic acids, were used as proxies for terrestrial vegetation type, aridity, and atmospheric circulation. Marine biomarkers, such as sterols and phytol, were used to reconstruct productivity in the Peru Margin upwelling zone, where sedimentary conditions are not conducive to the preservation of foraminifera. Through the use of organic molecular isotopic techniques and multi-molecular stratigraphy, a great deal can be learned about communities of marine organisms and terrestrial plants that existed in the past and the environments in which they lived.