About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
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| Symposium
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Four-Dimensional Scanning Transmission Electron Microscopy (4D STEM) for Quantitative Materials Characterization
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| Presentation Title |
Revealing multiple pathways of ringwoodite and wadsleyite formation in the Catherwood L6 shocked meteorite using SEM and STEM diffraction |
| Author(s) |
Tirzah Abbott, Collett Akins, Michael Barsoum, Laura L Gardner, Michael Hjelmstad, Xiaobing Hu, Omar K Farha, Aimo Winkelmann, Philipp R Heck, Roberto dos Reis, Thomas Sharp, Vinayak P Dravid, Steven Jacobsen |
| On-Site Speaker (Planned) |
Tirzah Abbott |
| Abstract Scope |
Shock-melt veins in ordinary chondrites preserve ultrafast high-pressure mineral transformations, but resolving the nanoscale reaction pathways responsible for their formation remains challenging. Here, we combine near-axis transmission Kikuchi diffraction (NA-TKD), 4D scanning transmission electron microscopy (4D-STEM), SEM, and EDS to characterize high-pressure olivine polymorphs within shock-melt veins of the Catherwood L6 chondrite. Host olivine along the shock-vein margin transforms into dense, randomly oriented ringwoodite crystallites, consistent with rapid solid-state transformation by intracrystalline nucleation and interface-controlled growth under strongly overstepped conditions. In contrast, olivine fragments entrained within the melt preserve ringwoodite-rich cores but develop Fe-rich reaction zones and Mg-rich wadsleyite rims at melt-wetted aggregate boundaries, accompanied by majoritic garnet. Together, these observations reveal a two-stage, spatially heterogeneous transformation sequence involving initial solid-state ringwoodite formation followed by localized melt-mediated overprinting and demonstrate how correlative nanoscale microscopy can reconstruct complex high-pressure reaction pathways in planetary materials. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Phase Transformations, Other, Nanotechnology |