The role of volcanism in the genesis of Early Cenozoic global warming events

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One approach to understanding the causes and consequences of rapid global warming is to study geological warming events - called 'hyperthermals' - that repeatedly punctuated the very warm climate state of the early Cenozoic Era (~60-52 Ma). One hypothesis for a control on the occurrence of hyperthermals is that they were triggered by volcanism associated with the North Atlantic Igneous Province (NAIP) in the interval ~60-50 Ma. These volcanic pulses could have delivered CO2 to the atmosphere and oceans either by direct outgassing, or by the thermal alteration of organic-rich rocks by magmatic intrusions. Although these relationships have been tested for the largest Eocene hyperthermal, the Paleocene-Eocene Thermal Maximum (PETM), the relationship between magmatic intrusions, thermogenic CO2 release, and the genesis of the many subsequent Early Eocene hyperthermal events remains untested. Knowing whether volcanism was responsible for triggering hyperthermals is an important task, to quantify the amount of CO2 released during each event; and to quantify the relationship between CO2-forcing and temperature change (climate sensitivity). This PhD project will apply cutting-edge proxy-data techniques for recognizing volcanism in the geological record, to a series of globally distributed sedimentary successions recording Early Eocene hyperthermal events. Sedimentary mercury concentrations will be used to reconstruct a history of volcanism associated with the NAIP from ~60-52 Ma. Secondly, the osmium-isotope composition of marine rocks will be used to trace the global geochemical fingerprint of volcanic-derived Os on ocean chemistry.