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

理解快速全球变暖的原因和后果的一种方法是研究地质变暖事件——被称为“超级热”——它反复打断了早期新生代（~60-52 Ma）的非常温暖的气候状态。控制热液发生的一种假设是，它们是由北大西洋火成岩省（NAIP）相关的火山活动在~60-50 Ma区间引发的。这些火山脉冲可以通过直接放出气体，或者通过岩浆侵入对富含有机物的岩石的热蚀变，将二氧化碳输送到大气和海洋中。尽管这些关系已经在始新世最大的热活动古新世-始新世热极大期（PETM）中得到了验证，但岩浆侵入、热成因CO2释放和随后的许多早始新世热活动的成因之间的关系仍未得到验证。了解火山活动是否引发了超热现象是一项重要的任务，可以量化每次事件中释放的二氧化碳量；以及量化二氧化碳强迫与温度变化（气候敏感性）之间的关系。该博士项目将应用前沿的代理数据技术来识别地质记录中的火山作用，以记录早始新世高温事件的一系列全球分布的沉积序列。沉积汞浓度将用于重建与NAIP有关的~60-52 Ma的火山活动历史。其次，利用海相岩石的锇同位素组成，追踪火山衍生Os在海洋化学中的全球地球化学指纹。

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.