VU Research Portal Mineralogical diversity and geology of Humboldt crater derived using Moon Mineralogy Mapper data Martinot, M.; Besse, S.; Flahaut, J.; Quantin-Nataf, C.; Lozac'h, L.; van Westrenen, W. published in Journal of Geophysical Research. Planets 2018 DOI (link to publisher) 10.1002/2017JE005435 document version Publisher's PDF, also known as Version of record Link to publication in VU Research Portal citation for published version (APA) Martinot, M., Besse, S., Flahaut, J., Quantin-Nataf, C., Lozac'h, L., & van Westrenen, W. (2018). Mineralogical diversity and geology of Humboldt crater derived using Moon Mineralogy Mapper data. Journal of Geophysical Research. 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Oct. 2021 Journal of Geophysical Research: Planets RESEARCH ARTICLE Mineralogical Diversity and Geology of Humboldt Crater 10.1002/2017JE005435 Derived Using Moon Mineralogy Mapper Data Key Points: • Multiple pure crystalline plagioclase M. Martinot1,2 , S. Besse3 , J. Flahaut4 , C. Quantin-Nataf2 , L. Lozac’h2, are detected in the Humboldt crater and W. van Westrenen1 central peak complex, hinting at its crustal origin 1Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands, 2Université Lyon 1, ENS-Lyon, CNRS, UMR • Olivine, spinel, and glass are 3 4 detected in the crater’s walls and rim, 5276 LGL-TPE, Villeurbanne, France, European Space Astronomy Centre, Madrid, Spain, Institut de Recherche en suggesting their shallow origin, Astrophysique et Planétologie, CNRS/UMR 5277, Université Paul Sabatier, Toulouse, France possibly linked to a plutonic event • Crater counts performed on the crater volcanic deposits suggest that Abstract Moon Mineralogy Mapper (M3) spectroscopic data and high-resolution imagery data sets volcanic activity in Humboldt crater 3 spanned over a billion years were used to study the mineralogy and geology of the 207 km diameter Humboldt crater. Analyses of M data, using a custom-made method for M3 spectra continuum removal and spectral parameters calculation, reveal multiple pure crystalline plagioclase detections within the Humboldt crater central peak complex, Supporting Information: • Supporting Information S1 hinting at its crustal origin. However, olivine, spinel, and glass are observed in the crater walls and rims, •DataSetS1 suggesting these minerals derive from shallower levels than the plagioclase of the central peak complex. High-calcium pyroxenes are detected in association with volcanic deposits emplaced on the crater’s floor. Correspondence to: Geologic mapping was performed, and the age of Humboldt crater’s units was estimated from crater counts. M. Martinot, Results suggest that volcanic activity within this floor-fractured crater spanned over a billion years. The felsic [email protected] mineralogy of the central peak complex region, which presumably excavated deeper material, and the shallow mafic minerals (olivine and spinel) detected in Humboldt crater walls and rim are not in accordance Citation: with the general view of the structure of the lunar crust. Our observations can be explained by the presence Martinot, M., Besse, S., Flahaut, J., of a mafic pluton emplaced in the anorthositic crust prior to the Humboldt-forming impact event. Quantin-Nataf, C., Lozac’h, L., & van Westrenen, W. (2018). Alternatively, the excavation of Australe basin ejecta could explain the observed mineralogical detections. Mineralogical diversity and geology of This highlights the importance of detailed combined mineralogical and geological remote sensing studies Humboldt crater derived using Moon to assess the heterogeneity of the lunar crust. Mineralogy Mapper data. Journal of Geophysical Research: Planets, 123. https://doi.org/10.1002/2017JE005435 Plain Language Summary Humboldt crater is a 207 km diameter complex impact crater located on the farside of the Moon. A central peak sits in its center, whereas its periphery is occupied by volcanic Received 4 SEP 2017 deposits. The peak was formed during the crater-forming impact event, as material from depth was brought Accepted 20 NOV 2017 up to the surface. In this study, we make use of the light that is reflected from the lunar surface to infer Accepted article online 21 DEC 2017 its composition. We used data from the Moon Mineralogy Mapper (M3) instrument, a visible near-infrared spectrometer, that orbited the Moon between 2008 and 2009. We surveyed the mineralogy of the different crater units and dated them by crater counts. We found that volcanic activity in Humboldt crater might have spanned over 1 Ga. Plagioclase minerals detected in the Humboldt crater central peak hints at its crustal origin, whereas the mineralogic assemblage of the crater walls and rim is more puzzling and raises questions about the lunar crust structure. 1. Introduction Studies of the structure of the lunar crust are important to constrain the magmatic and thermal evolution of the Moon (e.g., Shearer et al., 2006). The Lunar Magma Ocean (LMO) concept predicts that the upper part of the lunar crust was formed by floatation of plagioclase on a magma ocean, forming a >90% plagioclase-rich, anorthositic upper crust (e.g., Kaula, 1979; Warren, 1985). Denser minerals formed during the earlier stages of magma ocean crystallization (such as olivine and pyroxene) sank to the bottom the magma ocean, forming ©2017. The Authors. This is an open access article under the the lower crust and mantle (e.g., Lin et al., 2017; Snyder et al., 1992). terms of the Creative Commons Attribution-NonCommercial-NoDerivs A diversity of studies using different remote sensing data have been conducted in order to establish a lunar License, which permits use and crustal stratigraphy. Many of these focus on the mineralogical composition of the central uplift of impact distribution in any medium, provided craters, where material originating from greater depths is exposed (Cintala & Grieve, 1998). Scaling laws exist the original work is properly cited, the use is non-commercial and no to estimate the depth of origin of central uplift material, which is a function of the crater’s diameter (e.g., modifications or adaptations are made. Cintala & Grieve, 1998; Melosh, 1989). Tompkins & Pieters (1999) studied the mineralogy of lunar crater’s MARTINOT ET AL. HUMBOLDT CRATER MINERALOGY AND GEOLOGY 1 Journal of Geophysical Research: Planets 10.1002/2017JE005435 central peaks with Clementine data, and Wieczorek and Zuber (2001) linked the results with Clementine crustal thickness models. The authors observed an increase of the mafic mineral content with depth. More recently, studies highlighted variations in crustal composition that deviate from the global understand- ing of the lunar stratigraphy, pointing at the existence of significant heterogeneities within the crust. Song et al. (2013) used Lunar Reconnaissance Orbiter (LRO) Diviner data to calculate the Christiansen Feature (CF) value of lunar crater’s central peaks. The CF value is an infrared emission maximum, the position of which is indicative of bulk mineralogy (Logan et al., 1973). Song et al. (2013) results pointed at the presence of lateral and vertical heterogeneities in the crustal composition. Lemelin et al. (2015) worked with the SElenological and ENgineering Explorer (SELENE) Kaguya Multiband Imager (MI) data, which provides visible near-infrared multispectral images with five spectral channels. The authors found that mafic intrusions likely intruded the lunar crust in the Feldspathic Highland Terrane and that the Procellarum KREEP Terrane and the South Pole Aitken Terrane (introduced as FHT, PKT, and SPAT by Cahill et al., 2009) impact events probably incorpo- rated a mantle component in their melts. These results are generally consistent with the models of Head and Wilson (1992b), who proposed that buoyant diapirs of mantle might have intruded the base of the anorthositic crust during magma ocean crystallization, forming crustal heterogeneities (up to 50 % of the lower crust in volume, Head & Wilson, 1992a). Because the material emplaced in a crater’s central peak complex originates from deeper than the material observed in the crater’s walls, floor, and ejecta, detailed mineralogical and geological studies of impact craters can provide constraints on local crustal structure. Here we assess the mineralogy, geology, and morphology of the Humboldt crater central peak complex, floor, walls, and rim using Moon Mineralogy Mapper (M3) spectro- scopic data, combined with high-resolution imagery data sets. We present a custom-made method to remove the continuum of M3 spectra and to calculate spectral parameters. Our observations are aimed at shedding new light on the geology,