Morphometrics of regmaglypts based on a 3D Model of the fusion-crusted ordinary chondrite Broek in Waterland (L6)

Regmaglypts are shallow depressions on meteorite surfaces formed by ablation processes during atmospheric entry. These features can potentially offer insights in breakup events. However, quantitative methods to analyse regmaglypts have not yet been proposed to date. Here we present the results of a study to evaluate breakup processes during the luminous flight by analysing regmaglypt morphometrics. We developed a novel approach based on a 3D shape model of the Broek in Waterland meteorite that was generated using photogrammetry. We converted sections of the 3D model into a smoothed Digital Elevation Model (DEM) that contained the fracture surfaces adorned with regmaglypts. Lending techniques from terrain analyses, we extracted Land Surface Parameters (LSP) and delineated regmaglypts based on the mean curvature inflection point. The outliers of the regmaglypt population were discarded based on mean and total curvature scatter plots. The mean, profile, tangential, total and Gaussian curvatures were found to be most descriptive of regmaglypt morphologies. Various other curvature types were tested and found to be consistent across the studied regmaglypt population. Using this initial framework, we found that the two regmaglypted surfaces of the Broek in Waterland meteorite appear to be similar. This would reflect similar formative conditions, which we interpret to be most consistent with formation from the same breakup event. Future studies will aim to expand the presented method to regmaglypt populations of other L6 meteorites to understand how surface characteristics can inform us on ablation and breakup processes.