Isotopic interconnections in the earth system

这项拟议研究计划的总体目标是利用尖端的总硫和氧同位素测量来追踪“时间中的电子”。氧化还原变换和相关的电子流将固体地球及其流体包层的共同演化联系在一起。全球生物群调节了这些变化中的大部分，使地球表面环境的氧化还原轨迹能够被解释为生物进化的记录。在麦吉尔大学地球和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受限的现代环境的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，这些示踪剂然后被应用于岩石记录中特征良好的样本集。例如，即将开展的工作的重点将从现代甲烷水合物中的生物地球化学循环到关于岩浆脱气的活塞-圆柱体研究。一个共同的主题将是提取硫和氧的分馏系数，这是这些环境中物质循环的特征。在实验室调查的同时，实地研究将跨越地球历史的全部范围，从最近的火山喷发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给地球系统科学领域带来双重好处。首先，用于氧化还原转换的同位素示踪剂的校准将提供

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