Keywords: Volcanology, Python3, Open-source, Geochemistry, melt inclusions

Estimating the depth at which magma is stored in the crust and upper mantle below active volcanic systems is vital for decision making during volcanic crises, to understand the formation of critical metal deposits, and for models of continental crust formation. Petrologists use a variety of methods to estimate storage depths, such as performing detailed geochemical analysis of erupted crystal compositions, melt inclusions and fluid inclusions. However, the uncertainties associated with these methods have not been evaluated in detail, largely because calculations converting measured geochemical parameters into depths have thus far been performed in a myriad of different tools, mostly distributed in Excel. This has made it almost impossible to compare different models to assess systematic uncertainty, and propagate analytical errors to assess random uncertainty. By collating various existing tools into computationally-efficient, open-source Python3 packages, we have discovered that the errors on these methods often span the entire width of the crust, and can generate spurious pressure-temperature arrays masquerading as transcrustal storage. These errors raise questions about whether many widely-used techniques can actually provide insights into magma storage geometries. Careful choice of models and analytical conditions, along with recent advances in Raman spectroscopy, may provide a way forward.

Flyer: Wieser_Seminar_2022