Distinct Carbonate Lithologies in Jezero Crater, Mars

Abstract

Jezero crater is the landing site for the Mars 2020 Perseverance rover. The Noachian-aged crater has undergone several periods of fluvial and lacustrine activity and phyllosilicate- and carbonate-bearing rocks were formed and emplaced as a result. It also contains a portion of the regional Nili Fossae olivine-carbonate unit. In this work, we performed spectral mixture analysis of visible/near-infrared hyperspectral imagery over Jezero. We modeled carbonate abundances up to ∼35% and identified three distinct units containing different carbonate phases. Our work also shows that the olivine in Jezero is predominantly restricted to aeolian deposits overlying the carbonate rocks. The diversity of carbonate phases in Jezero points to multiple periods of carbonate formation under varying conditions.

Keywords: Martian geology; remote sensing; spectral analysis.

Figure 1

Summary of imagery and study area in this work. Yellow polygons outline the three CRISM images analyzed: FRT000047A3, FRT00005C5E, and HRL00040FF. Base image is a Context Imager (CTX) mosaic. CRISM, Compact Reconnaissance Imaging Spectrometer for Mars.

Figure 2

Cumulative abundance maps for (a) carbonate and (b) olivine. Outlines of the northern fan, Mottled Terrain, and the Light‐Toned Floor are from Goudge et al. (2015); the Marginal Carbonates are outlined based on Horgan et al. (2020).

Figure 3

(a) Carbonate and (b) olivine abundances at their respective 90th percentiles and above. (c and d) Mean measured and modeled spectra for 90th percentile pixels. Mean spectra from all three CRISM images have been averaged together to produce a single spectrum. The dashed line on (d) from ∼1.9 to 2.1 µm represents residual atmosphere not removed by the DISORT model. A full explanation is in the supplementary material. (e) Distribution of abundances for all groups for both the high‐carbonate and high‐olivine regions. All distribution plots in this paper are standard box and whisker plots. A more detailed explanation is in the supplementary material. CRISM, Compact Reconnaissance Imaging Spectrometer for Mars.

Figure 4

(a) Calcite, (b) magnesite, and (c) siderite abundance maps. The Marginal Carbonates are outlined again in (b).

Figure 5

(a) Close‐up of ROI. (b) Zoom to highlight contact between Marginal Carbonates and Mottled Terrain. (c–e) Abundance maps of the three main carbonate units, context boxes in Figure 1. (c) Marginal Carbonates with magnesite abundances overlain, (d) olivine‐rich sand with calcite abundances overlain, and (e) Mottled Terrain with siderite abundances overlain. Base image is the Murray Lab HiRISE mosaic E77‐25_N18‐5.tif.