Dust Provenance and ITCZ Migration

We are examining variations in dust deposition throughout the last 150,000 years in the west-central Pacific, near the Line Islands Ridge.  The sediment cores we are working on constitute a north-south transect across the modern Inter-Tropical Convergence Zone (ITCZ) near 160°W. We are targeting windblown dust because it plays important roles in influencing and recording climate change.  In the atmosphere, dust contributes to the planetary albedo and serves as cloud-condensation nuclei. In the ocean, dust may fertilize biological productivity through the addition of crucial trace nutrients, and provide ballast for the sinking of particles, thus enhancing carbon export from the surface ocean and drawing down atmospheric CO₂.  Therefore, in deep-sea sediments, the amount, location and type of dust deposition provide clues for reconstructing its past sources, pathways, magnitude and removal processes. This work is a collaborative project with colleagues at Columbia University.