Isotopic interconnections in the earth system

拟议研究计划的总体目标是使用最先进的硫和氧同位素总量测量来跟踪“电子穿越时间”。氧化还原转化和相关的电子流动将固体地球及其流体包膜的共同演化联系在一起。全球生物群介导了大部分这些转变，使地球表面环境的氧化还原轨迹可以被解释为生物进化的记录。在麦吉尔大学地球与行星科学系的稳定同位素实验室，我们利用实验室实验和对现代环境的良好约束研究来校准古氧化还原变化的硫和氧同位素示踪剂。一旦校准，这些示踪剂就会应用于岩石记录中具有良好特征的样品集。例如，未来工作的重点将从现代甲烷水合物的生物地球化学循环到岩浆脱气的活塞缸研究。一个共同的主题将是提取这些环境中表征物质循环的硫和氧分馏因子。在实验室调查的同时，实地研究将跨越整个地球历史，从最近火山爆发的产物到地球上一些最古老的岩石（Nuvvuagittuq绿岩带）。这项工作的成功完成将为地球系统科学领域提供双重利益。首先，氧化还原转化的同位素示踪剂的校准将提供一个

The broad objective of the proposed research program is to track 'electrons through time' using cutting-edge measurements of total sulfur and oxygen isotopes. Redox transformations, and the associated flow of electrons, link the co-evolution of the solid earth and its fluid envelope. The global biota mediate most of these transformations, enabling the redox trajectory of the earth surface environment to be interpreted as a record of biotic evolution. In the stable isotope laboratory of McGill University's Earth and Planetary Sciences department, we use laboratory experiments and studies of well-constrained modern environments to calibrate sulfur and oxygen isotopic tracers of paleoredox changes. Once calibrated, these tracers are then applied to well-characterized sample sets from the rock record. The focus of upcoming work, for example, will range from biogeochemical cycling in modern methane hydrates to piston-cylinder investigations on magmatic degassing. A common theme will be the extraction of sulfur and oxygen fractionation factors that characterize material cycling in these environments. Concurrent with laboratory investigations, field studies will span the full range of Earth history, from the recent products of volcanic eruptions to some of the oldest rocks of Earth (the Nuvvuagittuq greenstone belt). Successful completion of this work will provide a double benefit to the field of Earth System Science. First, the calibration of isotopic tracers for redox transformations will provide a