Tropical Southeast Pacific Continent-Ocean-Atmosphere Linkages Since the Pliocene Inferred from Eolian Dust

Abstract

Paleo-changes in trade-wind strength play a key role in the process of Pliocene and Pleistocene climate reorganization in the tropical oceans. In the Southeast Pacific, knowledge about changes in southeast trade-wind strength is one of the missing links to understand paleo-changes in oceanography and productivity, and associated variations in thermocline depth and upwelling. The area has long been in focus of the paleoclimate studying community due to the warm Pliocene's similarities to modern El-Niño conditions that turned into a dominant La-Niña-like state during the Pleistocene ice ages. Eolian dust is a valuable indicator of paleo-changes in atmospheric circulation and continental aridity. This thesis examines continent-ocean-atmosphere linkages in the tropical Southeast Pacific at selected time intervals during the Pliocene and Pleistocene epochs on the basis of eolian dust as preserved in marine sediments. The main objectives of this study are the reconstruction of changes in (1) southeast trade-wind strength and dust transport, and changes in (2) western South American continental aridity over time.