中科大地球与行星物理学术报告通知- Isabelle Daniel

报告人简介（续）：

Her interest is in the habitability of the Earth and planets and the origin of life, that she investigates through fluid-rocks interactions in the subsurface to evaluate the availability of nutrients, energy and building block of life for the subsurface biosphere on Earth or water-rich planets. Her expertise is in situ mineral physics and petrology using the diamond anvil cell coupled to spectroscopy (e.g., Raman, X-ray fluorescence, XANES). Through career, she has always served her community. She has chaired the geology department and the observatory of astrophysics, Earth and planetary sciences in Lyon for more than ten years. She has contributed to the international Deep Carbon Observatory project between 2010 and 2019, as an EC member and community leader. She is the acting president of the European Mineralogical Union. She is a fellow of the Mineralogical society of America, and was distinguished among the top influential Earth Scientist of the decade in 2021.

报告内容简介：

Cycling of carbon in subduction zones largely controls the atmospheric carbon dioxide and oxygen over Earth’s history. Carbon entering in subduction zones is transformed into fluids, magmas, volcanic gases and diamonds. Here I focus on the interactions between different forms of carbon compounds and the abundant aqueous fluids present in subduction zones as a result of the dehydration of minerals. I will present a study case of the solubility of calcite/aragonite and the subsequent speciation of and the dissolved species, corresponding to an oxidized environment. This case study emphasizes the abundance of ionic species in the deep aqueous fluids. Moving to more reduced conditions, I will show how small hydrocarbon form in deep aqueous fluids. Whether oxidized or reduced, these different forms of carbon have been described in deep fluid inclusions. Their occurrence in or as a fluid phase indicates that they are highly mobile. During their ascent, the abiotic reduced fluids may fuel deep subsurface life metabolic reactions potentially including anaerobic methane oxidation and methanogenesis, while the oxidized ones may fuel microbiota communities relying on CO₂ fixation. Two examples will be provided.