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Moonforming impact. During this period, the lunar magma ocean (LMO) lost most of its heat through early vigorous convection, crystallizing and forming an initial cumulate stratigraphy through, potentially, robust equilibrium crystallization followed by fractional crystallization once the LMO became sufficiently viscous. This rheological transition is estimated to have occurred at 50 % to 60 % LMO solidification, and although the petrological effects of the regime switch have been frequently investigated at the lower value, such effects at the upper limit have not been formally examined until now. Given this scenario, we present two new internally consistent, high-resolution models that simulate the solidification of a deep LMO of Earth-like bulk silicate composition at both rheological transition values, focusing on the petrological characteristics of the evolving mantle and crust. The results suggest that increasing the volume of early suspended solids from the oft-examined 50 % to 60 % may lead to non-trivial differences. The appearance of minor mantle garnet without the need to invoke a refractory-element enriched bulk silicate Moon composition, a bulk mantle relatively richer in orthopyroxene than olivine, a lower density upper mantle, and a thinner crust are shown to change systematically between the two models, favoring prolonged early crystal suspension. In addition, we show that late-stage, silica-enriched melts may not have sufficient density to permit plagioclase to continue building a floatation crust and that plagioclase likely sinks or stagnates. As the ability of a lunar magma ocean to suspend crystals is directly tied to the Moon’s early thermal state, the degree of early LMO convection – and the immediate Solar System environment that drives it – require as much consideration in LMO models as more well-investigated parameters such as bulk silicate Moon composition and initial magma ocean depth. 

This workshop will provide strategies and techniques for designing and executing computational petrology research projects and will engage participants in using software called Rhyolite-MELTS and the Magma Chamber Simulator (MCS) to address questions about open system magma evolution. Participants will: Be introduced to petrologic and geochemical questions that can be addressed by computational tools such as Rhyolite-MELTS and MCS. Be presented with case studies that utilize these computational tools to address petrologic questions. Be introduced to computational research design strategies and data management techniques. Learn the limits of thermodynamic databases and the functionality of computational methods when applied to natural systems. Collaborate and discuss strategies to apply these techniques to petrologic scenarios provided by the conveners. Have the opportunity to pose questions to MCS and Rhyolite-MELTS experts that will aid in the set-up of their computational projects. Network and benefit from the experiences and expertise of other scientists. Petrologists of all levels are encouraged to join the workshop! If you need training on the use of these tools, we will provide Zoom sessions prior to the workshop, with dates to be determined. If you have already taken an MCS workshop or attended a MELTS short course, please consider joining us again for additional training on research project design and execution. MCS and rhyolite-MELTS can also be used as teaching tools for those interested in integration into petrology/geochemistry classes, so please sign up if you would like to use these tools in your classes. The workshop will take place Tuesday, 1st October and Wednesday, 2 October, 08:00-13:30 MST/UTC-7 on both days. Registration is done through the Goldschmidt2024 conference registration form. If you are registering for the workshop only and not participating in the conference, on the Registration Options page of the form, under "Conference Options", please select "Science Workshop Only Remote (no conference attendance)", then choose this workshop in the section "Post-Conference Science Workshop: Remote (October 2024)" before proceeding to payment.