Heterogeneity of the Noachian Crust of Mars Using CRISM Multispectral Mapping Data. Issue 5 (24th February 2023)

• Record Type: Journal Article
• Authors: Viviano, Christina E.; Beck, Andrew W.; Murchie, Scott L.; Dapremont, Angela M.; Seelos, Frank P.
• Is Part Of: Geophysical research letters. Volume 50:Issue 5(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-02-24
• Subjects: Mars -- alteration and weathering processes -- hydrothermal systems and weathering on other planets -- remote sensing; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2022GL102711
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: We used Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) multispectral mapping data to assess heterogeneity of primary and secondary mineral compositions of Noachian‐aged regions of Martian crust. Multispectral data corroborate interpretations from CRISM targeted observations and Observatoire pour la Mineralogie, l'Eau, les Glaces et l'Activité global mapping of large horizontal differences in vertical crustal structures, and degree and grade of alteration to secondary minerals. CRISM multispectral data analysis conducted at a combination of high spatial resolution and coverage not available in other data sets also reveals previously unrecognized exposures. At one extreme, basaltic crustal material is minimally altered, mostly to smectite clay; at the other, Al‐enriched alteration products are present, alteration is widespread, and superposed surface materials rich in salts and precipitates, suggesting multiple episodes of alteration. The revealed vertical structure of primary mineralogy is consistent with that inferred in previous studies. Controls on the extent and metamorphic grade of secondary mineral assemblages are proximity to heat sources including large impact basins and inferred magmatic bodies. Plain Language Summary: We used the CRISM mapping spectral database with ∼86% coverage of the surface of Mars to confirm previously observed trends in the composition of crust exposed during different eras. The exposures of minerals that are formed through primary crust‐forming processes (e.g., volcanism) reveal distinct changes to mineral compositions through time. Secondary minerals formed through alteration of the primary crust also have a distinct signature with time and proximity to sources of heat: such as large basins that formed through giant impacts, and heat sources from magma reservoirs deep in the crust. Key Points: Previous data suggest heterogeneous primary and secondary mineralogy exposures in Noachian crust Compact Reconnaissance Imaging Spectrometer for Mars multispectral mapping data were used to study regions reported to exhibit differing degrees of alteration Heterogeneous alteration is confirmed and likely results from differences in heat availability