Description
Silicon (Si) is a key element in many Earth`s surface process and elemental cycles. It is mobilized during chemical weathering of solids, like silicates and (bio)opal, and transported within the hydro-, litho- and biosphere most prominently as silicic acid (H4SiO4), where it acts as nutrient and takes part in secondary precipitates such as authigenic clay minerals within the critical zone. Here, Si is suspected to initially precipitate as amorphous, gel-like phases including short-range ordered hydroxyalumosilicates or hydrous ferric silicates. Once it reaches the ocean it can be sequestered by silicifying organisms (e.g., diatoms or sponge spicules) to build their skeletons. During all these processes Si isotopes are fractionated between the reservoirs depending on individual and coupled reaction mechanisms and kinetics. Thus, Si isotope signatures can be used to track chemical (reverse) weathering and thus act as paleo-proxy for e.g. seawater evolution and climate change. However, Si isotope fractionation mechanisms during the weathering, precipitation, diagenesis are not yet well understood. Therefore, experimental and analytical concepts are introduced as a powerful tool to shed light onto these processes using high temporal resolution approaches to monitor the isotope fractionation kinetics, as well as the three-isotope method to investigate isotope equilibrium conditions. These concepts help to constrain the above-mentioned mechanisms, as well as the use of Si isotopes as paleo-proxy.| Period | 15 Nov 2023 |
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| Held at | Georg-August University Göttingen, Germany |