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Leah H. Joseph
Human-induced climate change is a major concern as climates are actively changing at rates that pose threats to human infrastructure, health, and ecosystems. Our research goal was to study the evolution of natural climatic conditions over the last 260,000 years in the eastern basin of the Pacific Ocean to see how Earth’s climate has reacted to a changing climate in the past. We analyzed deep ocean sediment collected from Site 1233 of the Ocean Drilling Program’s Leg 202 off the western coast of Chile. We performed a chemical extraction of biological material and ocean-derived sediment coatings from our samples to isolate the terrigenous, continentally-derived, component, removing carbonate and silicate shells, oxide/hydroxide coatings, and the grains >63 microns in diameter. We then calculated a terrigenous mass accumulation rate (t-MAR) using the sample’s before- and after-extraction weight, combined with other parameters determined shipboard. This calculation can offer insights into erosion rates and sediment transport mechanisms throughout the 260,000-year history, allowing for interpretation of climatic conditions on the nearby continent. High t-MAR values may reflect a wetter climate, capable of depositing grains into the ocean. Smaller t-MAR values may indicate a drier climate, where the continental sediment is transported via dust in the wind. In conjunction with grainsize and magnetic fabric analyses which indicate relative changes in ocean current speeds, our combined investigation will further characterize the Site’s climatic conditions. Overall, we hope that our research will contribute to the understanding of current climate data and help inform decisions as human-induced climate change continues.
Duimering, Abigail, "Investigating Paleoclimate of the Chilean Margin and its Evolution Through Analysis of Deep Ocean Sediment" (2023). Environmental Studies Summer Fellows. 17.
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