201-5 Uncovering Martian Crustal Evolution: Preliminary Results from Global Primary Mineral Mapping with CRISM

Session: The G.K. Gilbert Award Session: Geology of Mars, Mercury, Asteroids, and Icy Satellites in Honor of Scott Murchie

Presenting Author:

Samuel Cartwright

Authors:

Cartwright, Samuel F. A.¹, Jandai, Tahn², Phillips, Michael Steven³, Viviano, Christina⁴, Seelos, Frank⁵, Kinczyk, Mallory Janet⁶, Hancock, Katie⁷

(1) Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, Boulder, CO, USA, (2) Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, Boulder, CO, USA, (3) Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA, (4) Johns Hopkins Applied Physics Laboratory, Laurel, MD, USA, (5) Johns Hopkins Applied Physics Laboratory, Laurel, MD, USA, (6) Johns Hopkins Applied Physics Laboratory, Raleigh, NC, USA, (7) Johns Hopkins Applied Physics Laboratory, Laurel, MD, USA,

Abstract:

Unlike on Earth and Venus where early crustal materials have been buried, recycled, or destroyed, the surface of Mars preserves a record of the planet’s crustal formation and evolution spanning ~4.55 Ga—nearly the lifetime of the Solar System. A rough understanding of this history is provided by crustal composition. Olivine and low-calcium pyroxene (LCP) dominate pre- to early-Noachian (≳3.9 Ga) crust although a number of more evolved “feldspathic” outcrops have also been identified in these terrains. LCP with local regions of olivine enrichment define mid- to late-Noachian (~3.9–3.7 Ga) crust. Higher proportions of high-calcium pyroxene (HCP) compared to LCP and olivine distinguish the Hesperian to Amazonian (≤3.7 Ga). These general associations are useful, but the limited extents and/or resolutions of existing primary mineral maps have left many questions about Mars’s crustal evolution unresolved. Are mantle heterogeneities captured in regional trends of primary mineral exposures? Are impact melt deposits from the hypothesized dichotomy-forming impact preserved at the surface? What is the full extent and nature of evolved/feldspathic outcrops? 

 

New mosaics from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) now allow primary minerals to be mapped at 180 m/pixel, with 72 visible-to-near-infrared channels, across a near-global extent (~78% coverage between ±67.5°N). To generate a global inventory of primary mineral exposures with this dataset, we have produced an expanded suite of spectral parameters that can capture subtle spectral shifts in exposures with varying proportions of LCP, HCP, olivine, plagioclase feldspar, and Fe-bearing glass. We are using these parameters alongside the standard CRISM set to identify and map the extent of spectrally distinct primary mineral species and mixtures thereof with unsupervised and statistics-based classification methods. The classified CRISM mosaics will be converted to GIS-ready vector maps using a new open-source Python library we have developed called vectroscopy, allowing for derived analyses that can reveal spatial trends and outliers in crustal composition across Mars. The results of this work will help to constrain remaining unknowns about the planet’s crust and the crustal evolution of the rocky planets more generally.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

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