The Fate of Subducted Carbon Dioxide During Metamorphism, Syros and Tinos Islands, Greece

地球的俯冲带以深海海沟为标志，在那里一个构造板块下沉（俯冲）到另一个板块之下进入地幔，通常以每年几英寸的速度。俯冲带具有至关重要的社会意义，因为它们是世界上最大的地震-包括那些产生致命海啸的地震-和最具破坏性的火山。此外，俯冲是地质碳循环的驱动力，是地球温带气候和生命的先决条件。每年大约有一亿吨储存在岩石中的碳在地球仪上被消减。然而，围绕这些碳中有多少（主要以二氧化碳的形式）实际上是从俯冲带释放出来并返回地表的，存在重大分歧。这些二氧化碳主要是被带到地幔深处，还是大部分上升到最终与大气和水圈相互作用？拟议的工作将阐明这些问题，确定的性质，过程和数量的碳运输记录的锡罗斯和蒂诺斯群岛，希腊的化石俯冲复合体暴露。这是量化自然和人为（人类）对气候和气候变化长期演变的贡献的必要步骤。拟议的工作是一个基于野外的岩石学研究的变质脱碳酸作用过程，涉及蛇纹岩-榴辉岩（锡罗斯，蒂诺斯）和变质沉积榴辉岩（蒂诺斯）夹层或构造并列与变质火山岩，变质火山岩，变质火山岩。将量化含碳酸盐岩的封闭和开放系统行为，以确定外部流体渗透的程度，并绘制流体成分和时间积分脱挥发分通量图。这在俯冲复合体的区域尺度上是前所未有的。该提案的目标将通过以下方式实现：根据测得的岩石和矿物成分对流体化学进行热力学建模;对流体包裹体进行拉曼光谱分析，以确定含有溶解溶质的简单（例如水-二氧化碳）或更复杂的流体;开展氧和碳稳定同位素工作，以评估流体来源和流动路径;进行矿物和大块岩石化学分析，以确定交代反应。对二氧化碳迁移的定量估计将为地质碳循环模型提供重要的新投入。这项工作将支持博士学位。该项目为来自科学界代表性不足的群体的学生以及几名本科生提供了培训，并为耶鲁皮博迪自然历史博物馆和希腊克里特岛自然历史博物馆制作了关于碳循环的教育模块。

Earth's subduction zones are marked by the deep ocean trenches where one tectonic plate sinks (subducts) beneath another into Earth's mantle, commonly at speeds of inches per year. Subduction zones are of critical societal importance because they host the world's largest earthquakes - including those that produce deadly tsunamis - and the most destructive volcanoes. Moreover, subduction is a driver of the geological carbon cycle, a prerequisite for Earth's temperate climate and life. Roughly a hundred million tons of carbon stored in rocks are subducted each year across the globe. Yet major disagreements surround how much of this carbon, mostly in the form of carbon dioxide, is actually released from subduction zones to make the journey back to the surface. Is this carbon dioxide largely taken deep into Earth's mantle, or does the bulk of it ascend to ultimately interact with the atmosphere and hydrosphere? The proposed work will shed light on these questions by determining the nature, processes, and amounts of carbon transport recorded by the spectacularly-exposed fossil subduction complexes of Syros and Tinos islands, Greece. This is a necessary step for quantifying natural and anthropogenic (human) contributions to the long-term evolution of climate and climate change. The proposed work is a field-based petrological study of metamorphic decarbonation processes involving serpentinite-chlorite mélange (Syros, Tinos) and metasedimentary mélange (Tinos) intercalated or tectonically juxtaposed with metavolcanic, metaclastic, and metacarbonate rocks. The closed- and open-system behavior of carbonate-bearing lithologies will be quantified to determine the degree of external fluid infiltration and make maps of fluid composition and time-integrated devolatilization fluxes. This has not been done before at a regional scale in subduction complexes. The proposal goals will be achieved via thermodynamic modeling of fluid chemistry based on measured rock and mineral compositions; Raman spectroscopy of fluid inclusions to identify simple (e.g. water-carbon dioxide) or more complex fluids containing dissolved solutes; oxygen and carbon stable isotope work to assess fluid sources and flow pathways; and mineral and bulk-rock chemical analyses to determine metasomatic reactions. Quantitative estimates of carbon dioxide transport will provide important new inputs to models of the geologic carbon cycle. The work will support a Ph.D. student from an under-represented group in science as well as several undergraduates, and produce educational modules about the carbon cycle for both the Yale Peabody Museum of Natural History and the Natural History Museum of Crete, Greece.