# Abrasion Patch Dehydration Experiment at Bright Angel, Jezero Crater, Using SuperCam Onboard the Mars 2020 Perseverance Rover

S A Connell, R C Wiens, L. Mandon, C C Bedford, S. Siljeström, S. Schröder, G M Martínez, Á Vicente-retortillo, E A Cloutis, D M Applin, et al.

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## To cite this version:

S A Connell, R C Wiens, L. Mandon, C C Bedford, S. Siljeström, et al., Abrasion Patch Dehydration Experiment at Bright Angel, Jezero Crater, Using SuperCam Onboard the Mars 2020 Perseverance Rover. Journal of Geophysical Research. Planets, 2025, 130 (12), 10.1029/2025JE009243. hal-05411741

HAL Id: hal-05411741

https://hal.sorbonne-universite.fr/hal-05411741v1

Submitted on 11 Dec 2025

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Distributed under a Creative Commons Attribution 4.0 International License
JGR Planets

RESEARCH ARTICLE

10.1029/2025JE009243

**Key Points:**

* The Mars 2020 *Perseverance* rover produces abrasion patches to investigate fresh rock surfaces at Jezero crater, Mars

* The SuperCam instrument conducted the first in situ rover-based dehydration experiment in an abrasion patch of a rock exposure

* No hydration changes were observed, suggesting that the exposed minerals were already in a low hydration state and/or exhibit high stability

**Supporting Information:**

Supporting Information may be found in the online version of this article.

**Correspondence to:**

S. A. Connell,
connel47@purdue.edu

**Citation:**

Connell, S. A., Wiens, R. C., Mandon, L., Bedford, C. C., Siljeström, S., Schröder, S., et al. (2025). Abrasion patch dehydration experiment at Bright Angel, Jezero crater, using SuperCam onboard the Mars 2020 perseverance rover. *Journal of Geophysical Research: Planets*, 130, e2025JE009243. https://doi.org/10.1029/2025JE009243

Received 12 JUN 2025

Accepted 21 NOV 2025

**Author Contributions:**

**Conceptualization:** S. A. Connell

**Data curation:** S. A. Connell

**Formal analysis:** S. A. Connell, L. Mandon, C. C. Bedford, S. Siljeström, S. Schröder, G. M. Martínez, Á. Vicente-Retortillo, E. A. Cloutis, D. M. Applin, A. Broz, C. Royer, J. R. Johnson

**Funding acquisition:** R. C. Wiens

**Investigation:** S. A. Connell

**Methodology:** S. A. Connell

**Project administration:** S. A. Connell

**Resources:** S. A. Connell, R. C. Wiens

**Supervision:** R. C. Wiens

**Validation:** S. A. Connell, R. C. Wiens

© 2025. The Author(s).
This is an open access article under the
terms of the Creative Commons
Attribution License, which permits use,
distribution and reproduction in any
medium, provided the original work is
properly cited.

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Abrasion Patch Dehydration Experiment at Bright Angel, Jezero Crater, Using SuperCam Onboard the Mars 2020 Perseverance Rover

S. A. Connell¹ ID, R. C. Wiens¹ ID, L. Mandon² ID, C. C. Bedford¹ ID, S. Siljeström³ ID, S. Schröder⁴ ID, G. M. Martínez⁵, Á. Vicente-Retortillo⁵ ID, E. A. Cloutis⁶ ID, D. M. Applin⁶, A. Broz¹ ID, C. Royer⁷, J. R. Johnson⁸ ID, J. Van Beek⁹, T. Nelson¹⁰, E. Clavé⁴ ID, F. Poulet⁷, P. Beck² ID, E. Dehouck¹¹ ID, T. Fornaro¹² ID, T. Fouchet¹³ ID, A. Jones¹⁴ ID, A. Alberini¹² ID, A. Cousin¹⁵ ID, K. Hand⁹ ID, K. Uckert⁹ ID, J. A. Rodríguez-Manfredi⁵, K. M. Stack⁹ ID, and the Mars 2020 team

¹Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN, USA, ²Université Grenoble Alpes, CNRS, IPAG, Grenoble, France, ³RISE Research Institutes of Sweden, Stockholm, Sweden, ⁴German Aerospace Center (DLR), Institute of Space Research, Berlin, Germany, ⁵Centro de Astrobiologia (INTA-CSIC), Madrid, Spain, ⁶Centre for Terrestrial and Planetary Exploration, University of Winnipeg, Winnipeg, MB, Canada, ⁷IAS, Université Paris-Saclay, CNRS, Orsay, France, ⁸Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA, ⁹Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA, ¹⁰Los Alamos National Laboratory, Los Alamos, NM, USA, ¹¹Université Claude Bernard Lyon 1, ENS de Lyon, CNRS, UJM, LGL-TPE, UMR 5276, Villeurbanne cedex, France, ¹²INAF - Astrophysical Observatory of Arcetri, Florence, Italy, ¹³LIRA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, Meudon, France, ¹⁴Imperial College London, London, UK, ¹⁵Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse 3 Paul Sabatier, CNRS, CNES, Toulouse, France

**Abstract** Investigating the stability of hydrated minerals is integral for examining the preservation of rocks for potential Mars Sample Return and has major implications for models that use rover-based observations to quantify Mars' global water budget. The Mars 2020 *Perseverance* rover produces abrasion patches to investigate fresh rock surfaces at Jezero crater, Mars. However, due to operational constraints, the full analysis process typically takes several martian days (sols), and freshly exposed hydrated minerals may dehydrate upon atmospheric exposure between abrasion patch creation and their analyses. To assess the potential for short-term dehydration, the SuperCam instrument conducted the first in situ rover-based dehydration experiment on rock exposures of the “Bright Angel formation.” The SuperCam and SHERLOC rover instruments indicated that the primary mineral hydration phases were Fe-hydroxides, Ca-sulfates such as bassanite (mixed with anhydrite), with possible minor contributions from non-interlayer-water phyllosilicates (e.g., hydroxyl-bearing only). The experiment involved a four-sol sequence of observations on the Steamboat Mountain abrasion patch, beginning just 22 min after abrasion. Dehydration was assessed by tracking changes in the 1.93 µm H₂O absorption feature, which is sensitive to structural, absorbed, and adsorbed water. No significant changes in hydration were observed over the 93 hr, suggesting that the exposed minerals were already in a low hydration state and/or exhibit high stability under current martian surface conditions. These findings imply bulk rocks with low hydration and high stability minerals may not dehydrate upon exposure to the modern martian atmosphere on short time scales, consistent with predictions from laboratory simulations of Mars-like environments.

**Plain Language Summary** Scientists have long explored Mars due to its evidence for past water, which is essential for life. Understanding Mars' aqueous history is key to determining whether the planet was once habitable. We investigated this by studying water-bearing minerals, which can preserve clues about past water activity on Mars. This study investigates how minerals on Mars may lose water (e.g., dehydrate) after the rover removes ~1 cm of rock depth, exposing the fresh surface to the atmosphere. Using the SuperCam instrument onboard the Mars 2020 *Perseverance* rover, we conducted a first-time dehydration experiment on rocks from the “Bright Angel formation,” by observing changes in bulk rock water content over 4 days. Our results showed no significant loss of water from the minerals up to 93 hr of exposure. This suggests that the minerals were likely stable, meaning they didn't dehydrate after exposure to current martian surface conditions. These findings suggest that certain minerals on Mars may preserve water for longer periods or will not dehydrate further if they are already in a low hydration state. This study contributes to our understanding of ancient water
**Visualization:** S. A. Connell, L. Mandon, C. C. Bedford, S. Siljeström, S. Schröder, G. M. Martínez, Á. Vicente-Retortillo, E. A. Cloutis, D. M. Applin, J. R. Johnson, J. Van Beek, T. Nelson, E. Clavé

**Writing – original draft:** S. A. Connell
**Writing – review & editing:**

S. A. Connell, R. C. Wiens, L. Mandon, C. C. Bedford, S. Siljeström, S. Schröder, G. M. Martínez, Á. Vicente-Retortillo, E. A. Cloutis, D. M. Applin, A. Broz, C. Royer, J. R. Johnson, J. Van Beek, T. Nelson, E. Clavé, F. Poulet, P. Beck, E. Dehouck, T. Fornaro, T. Fouchet, A. Jones, A. Alberini, A. Cousin, K. Hand, K. Uckert, J. A. Rodríguez-Manfredi, K. M. Stack

on Mars, helping us identify potential past habitable environments and providing critical insights into planned Mars Sample Return.

# 1. Introduction

Water is key to martian habitability, but the hydration state of minerals on Mars is incompletely constrained (e.g., Scheller et al., 2021; Siljeström et al., 2024). Therefore, detecting hydrated minerals and understanding their hydration state and distribution is vital for uncovering martian geologic, hydrologic, and atmospheric evolution (e.g., Chipera et al., 2023; Siljeström et al., 2024; Vaniman et al., 2004, 2018). Moreover, the significance of Mars' current inventory of hydrated minerals is integral to understanding Mars' ancient aqueous history, as many of these minerals are preserved in thick, layered sedimentary deposits that are naturally exposed at the surface of Mars. Ancient water and hydroxyl from Mars' past have been sequestered and are locked within these minerals, and it is important to quantify how much of the global water reservoir remains (e.g., Mustard, 2019; Scheller et al., 2021). Global water budgets for Mars rely on orbital and in situ rover observations of bulk rock containing hydrated minerals (expressed as wt.% H₂O of bulk samples; e.g., Riu et al., 2023; Scheller et al., 2021). Current models rely strongly on observations of the top few microns of the surface (e.g., X-ray, visible, and infrared observations), which can be affected by modern environmental processes on Mars, such as dehydration. These environmental processes can be driven by surface-atmosphere exchanges, which play a key role in the atmospheric water cycle and influence processes on diurnal and seasonal timescales (e.g., Montmessin et al., 2024). Hence, determining the long-term stability of hydrous minerals is essential to understanding Mars' water inventory, which can be investigated using a variety of techniques.

Various orbital and ground-based instruments on Mars are used to characterize hydrous minerals (OH/H₂O) and to assess martian surface conditions. Most notable from orbit is the Mars Odyssey spacecraft's Gamma-Ray and Neutron Spectrometers (Boynton et al., 2004), the Observatoire pour la Minéralogie, l'Eau, les Glaces, et l'Activité (OMEGA) on board the Mars Express orbiter (Bibring et al., 2005), and the Compact Reconnaissance Imaging Spectrometer for Mars on the Mars Reconnaissance Orbiter (Murchie et al., 2007); and on the surface, instruments onboard the Mars Science Laboratory (MSL) *Curiosity* rover, such as the Chemistry and Mineralogy (CheMin) and Sample Analysis at Mars (SAM) spectrometers (Blake et al., 2012; Mahaffy et al., 2012), and the Rover Environmental Monitoring Station (Gómez-Elvira et al., 2012). Relevant instruments onboard the Mars 2020 *Perseverance* rover include SuperCam, Scanning Habitable Environments with Raman & Luminescence for Organics and Chemicals (SHERLOC), Planetary Instrument for X-Ray Lithochemistry (PIXL), and the Mars Environmental Dynamics Analyzer (MEDA; Allwood et al., 2020; Bhartia et al., 2021; Maurice et al., 2021; Rodriguez-Manfredi et al., 2021; Wiens et al., 2020). These orbital and in situ instruments can be used to investigate the hydration state, martian habitability, and the potential for biosignature preservation on Mars (Farley et al., 2020; Grotzinger et al., 2012; Murchie et al., 2007).

## 1.1. Perseverance's Exploration of Jezero Crater, Mars

The Mars 2020 *Perseverance* rover is exploring the Noachian-age Jezero crater (3.82–3.96 Ga), in search of areas with astrobiological potential (e.g., Farley et al., 2020; Horgan et al., 2020; Mandon et al., 2020; Werner, 2008). The crater's geological features and composition strongly indicate the presence of past liquid surface water, making it a prime candidate for habitability and the potential preservation of life (Ehlmann et al., 2011; Fassett & Head, 2005; Goudge et al., 2015, 2017; Schon et al., 2012). Along the rover traverse, there are geological units consisting of igneous formations (e.g., Séitah and Máaz) that show evidence of aqueous alteration (Farley et al., 2022; Mandon, Quantin-Nataf, et al., 2023; Scheller et al., 2022; Sun et al., 2023; Wiens et al., 2022), as well as sedimentary deposits (e.g., western fan and Kodiak; Mangold et al., 2021; Phua et al., 2024; Stack et al., 2024). The western fan is divided into two formations, the Shenandoah formation at the fan front (Stack et al., 2024), and the Tenby formation at the upper fan (fan top; Siebach et al., 2023). The rover also explored the crater's carbonate-bearing Margin Unit (Bedford, Ravanis, et al., 2025; Bedford, Wiens, et al., 2025) and the crater rim, which contains igneous and altered rocks (e.g., Bedford, Ravanis, et al., 2025; Bedford, Wiens, et al., 2025; Udry et al., 2025).
Jezero crater's igneous and sedimentary formations experienced multiple episodes of water activity, resulting in assemblages of secondary and hydrated minerals. Previously reported OH/H₂O-bearing phases in Jezero crater include hydrated silicates, Mg/Fe/Al phyllosilicates, kaolin-group minerals, Fe-oxyhydroxides, perchlorates/chlorates, hydrous carbonates, as well as variably hydrated Mg- and Ca-sulfates (Beck et al., 2025; Clavé et al., 2023; Corpolongo et al., 2023; Hausrath et al., 2023; Mandon, Quantin-Nataf, et al., 2023; Phua et al., 2024; Razzell Hollis et al., 2022; Royer, Bedford, et al., 2024; Royer, Bernard, et al., 2024; Scheller et al., 2022; Sharma et al., 2023; Siljeström et al., 2024; Srivastava et al., 2025; Tice et al., 2022). Given the water/hydroxyl stored within rocks at the surface of Jezero crater today, it is important to understand the various environmental conditions that can affect the stability of water-bearing minerals in the ancient, aqueously altered rocks of Jezero crater and in other regions on Mars.

## 1.2. Stability of Hydrated Minerals on Mars

To characterize the hydration state of rocks and regolith at Jezero crater, we must first understand the modern Mars environment. Exposure to current martian surface conditions, such as low relative humidity (RH), low atmospheric pressure (predominantly CO₂), variations in surface and near-surface temperatures, UV irradiation, and solar radiant heat (Alberini et al., 2024; Fischer et al., 2019; Mahaffy et al., 2013; Martínez et al., 2017; Munguira et al., 2023; Nayama Valsa Scariah et al., 2023; Patel et al., 2004; Spanovich et al., 2006), can affect hydroxyl- and water-rich minerals on Mars. These environmental parameters have been used to simulate Mars' surface conditions in laboratory settings to investigate the stability of Mars' relevant minerals (e.g., Alberini et al., 2024; Applin et al., 2015; Bish et al., 2003; Bishop & Pieters, 1995; Chauviré et al., 2021; Cloutis et al., 2007, 2008; Connell, Applin, et al., 2025; Fornaro et al., 2020; Milliken & Mustard, 2005; Morris et al., 2010; Mukhin et al., 1996; Poitras et al., 2018; Royer, Bernard, et al., 2024; Treiman et al., 2014; Turenne et al., 2022; Wang et al., 2009).

Laboratory experiments highlight the significance of investigating hydrated minerals to better understand their properties and stability under Mars-like surface conditions. Previous laboratory studies that investigated the stability of Mars-relevant minerals have used various durations of time in a simulated martian environment. During exposure to current Mars surface conditions, some minerals can dehydrate rapidly (e.g., within 24 hr) or gradually, based on the mineral type (e.g., Connell, Applin, et al., 2025). The minerals that show the most significant instability (e.g., most prone to dehydration) are water-bearing minerals such as hydrous carbonates, hydrated silicates, Mg/Ca-sulfates, some Al/Mg/Fe phyllosilicates, smectites, and hydrated micas (e.g., Alberini et al., 2024; Cloutis et al., 2007, 2008; Connell, Applin, et al., 2025; Fornaro et al., 2020; Poitras et al., 2018; Turenne et al., 2022). Spectra observed in these studies (covering 0.35–2.50 µm) showed loss of adsorbed and absorbed water and, in some cases, changes to hydroxyl-bearing absorption bands.

Many minerals studied in the Mars laboratory chambers have been found in Jezero crater by rover instruments on the natural surface and in abrasion patches (e.g., Beck et al., 2025; Clavé et al., 2023; Corpolongo et al., 2023; Dehouck et al., 2023; Mandon, Quantin-Nataf, et al., 2023; Phua et al., 2024; Razzell Hollis et al., 2022; Royer, Bedford, et al., 2024; Scheller et al., 2022; Siljeström et al., 2024). A variety of rocks along the rover's traverse exhibited a ~1.93 µm H₂O absorption band in SuperCam near-infrared reflectance spectra (e.g., Beck et al., 2025; Dehouck et al., 2023; Fouchet et al., 2022; Mandon, Quantin-Nataf, et al., 2023; Royer, Bedford, et al., 2024). From the laboratory experiments, we can understand mineral stability on Mars and predict the potential short-term effects of exposing fresh subsurface minerals to the modern martian environment. However, a better way to study the short-term behavior of hydrated minerals exposed to Mars surface conditions would be to observe that behavior directly on Mars over several days after the *Perseverance* rover creates a fresh abrasion patch.

Having introduced the importance of understanding the stability of hydrated minerals, Section 2 provides the geological context of the Bright Angel formation in Jezero crater and outlines the observational constraints of the *Perseverance* rover. Section 3 describes the methods employed by the rover's instruments and details the experimental setup, including the in situ dehydration experiment conducted with SuperCam for the first time to measure mineral stability. Section 4 presents the experiment's compositional, mineralogical, and hydration results, along with data from other abrasion patches along the rover's traverse. Section 5 discusses the bulk hydration state of Jezero, mineral stability at the rover's workspace, environmental conditions within the crater, and the need for future dehydration experiments on Mars. Finally, Section 6 summarizes our key findings and insights.
<figure><img src="image_4.png" /><figcaption>**Figure 1.** (a) A context image of the orbital HiRISE map of Jezero crater and the *Perseverance* rover's traverse (white line with white dots representing each stop) up to sol 1429 (blue dot, Longitude: 77.2°, Latitude: 18.4°, Elevation: -1848.3 m) through Neretva Vallis (the yellow box inset includes the Bright Angel (north) and Masonic Temple (south) exposures). (b) The Bright Angel formation orbital image showing the SBM (sol 1191) abrasion patch's location, next to the Apollo Temple abrasion (sol 1211) at Cape Solitude near Pearce Canyon in the Beaver Falls (green stars) rover workspace (at the northern Margin Unit contact), and the Walhalla Glades (sol 1179) abrasion patch (orange star) location to the south of the Bright Angel locality. (c) Mastcam-Z natural color mosaic (sol 1217; zcam09264) of the Beaver Falls outcrop with a white dashed line indicating the contact between rubbly coarser-grained texture of the Fern Glen Rapids member (right) and finer-grained crosscut lithology of the Cheyava Falls member (left); Sapphire Canyon is the sample collected at the Beaver Falls outcrop from the Cheyava Falls member. The tailings (loose powder) result from abrading and core sampling. (d) Natural color high-resolution WATSON image of SBM showing visual heterogeneity of white patches in a reddish-brown matrix (circular edge is the 4.5 cm abrasion diameter at a depth of 6.8 mm), NASA/JPL/Caltech/ASU/MSSS.</figcaption></figure>

**2. Geological Context and Observational Constraints**

**2.1. Geological Context of the Bright Angel Formation**

Neretva Vallis is an ancient river channel that was the primary inlet in the western margin of Jezero crater. This ancient river channel exposes a light-toned outcrop informally named Bright Angel (Figure 1a) that was explored
at two main locations: in the North at Bright Angel and in the South at Masonic Temple, both at the contact, next to the olivine- and carbonate-rich Margin Unit (Hurowitz et al., 2025; Jones et al., 2025; Mandon et al., 2025). This work focuses on the northern exposure of the Bright Angel formation, which stretches at least 1.2 km from the northern edge of Neretva Vallis to the inner floor (toward the south). *Perseverance* abraded three times within Bright Angel, creating the Steamboat Mountain (SBM), Apollo Temple, and Walhalla Glades abrasion patches (Figure 1b; Barnes et al., 2025; Hurowitz et al., 2025; Mandon et al., 2025). Unlike the adjacent Margin Unit, Bright Angel is a light-toned banded unit dominated by fine-grained mudstone to siltstone lithologies in the center of the channel, with coarser-grained intervals closer to the contact with the Margin Unit (Barnes et al., 2025; Hurowitz et al., 2025). Throughout the Bright Angel formation, diagenetic features such as Ca-sulfate nodules, Ca-sulfate veins, and Fe-phosphate nodules are present. The formation's textures suggest it is sedimentary in nature, with facies consistent with deposition in a lacustrine environment (Jones et al., 2025). Bright Angel's fine-grained component is primarily finely-crystalline and is composed of aluminosilicates and Ca-sulfates (Hurowitz et al., 2025; Mandon et al., 2025). The light-toned bedrock is relatively poor in carbonate with no olivine; however, some geological members at the contact contained mm-scale olivine grains/crystals within Ca-sulfate veins and in the rock matrix (Barnes et al., 2025; Connell, Wiens, et al., 2025; Hurowitz et al., 2025; Mandon et al., 2025). Moreover, the Bright Angel formation is astrobiologically relevant because of detections of Fe-phosphate, trace carbonate, and carbon-rich organics (Hurowitz et al., 2025; Murphy et al., 2025).

At the northern exposure of Bright Angel, *Perseverance* abraded at the Beaver Falls outcrop (in the rover workspace), close to the Margin Unit contact (Figure 1b). Here, we will focus on the Fern Glenn Rapids member (Figure 1c) where the SBM abrasion is located (Figure 1d), which stratigraphically overlies the Cheyava Falls member. The latter is where the Apollo Temple abrasion is located, and where the Sapphire Canyon sample was taken (Figure 1c). These two geological members show textural variability and are separated by a geologic boundary indicated by a dashed line in Figure 1c. Fern Glenn Rapids is a dark-toned granular conglomerate that is weakly stratified at the northern Margin Unit contact, and the Cheyava Falls member is a mudstone with parallel light-toned fracture fills (Jones et al., 2025).

## 2.2. Perseverance Rover Operations and Abrading Process

The *Perseverance* rover is equipped with a rotary-percussive drill with a rock-abrading bit to reveal the pristine martian subsurface by removing surface weathering, dust coatings, and rinds to a minimum depth of 2 mm and a maximum of 16 mm from the point of highest topography across the full 45 mm diameter of the abrasion patch (Moeller et al., 2020). After the surface abrasion occurs, the resulting tailings are removed from within the abrasion patch using the Gas Dust Removal Tool (gDRT). This enables precise targeting by rover instruments within the freshly exposed rock (Moeller et al., 2020). Post-abrasion, proximity science (SHERLOC and PIXL) and remote sensing instrument measurements (SuperCam and Mastcam-Z; Bell et al., 2021) occur in a specific order over several sols (sol = martian day). Due to Mars rover resources and power constraints, the typical minimum time between abrasion and proximity science is between 27 and 34 hr. Because of the prioritization of the proximity instruments, the typical minimum time between abrasion and remote sensing with SuperCam is approximately 44 hr. Therefore, the abrasion process and subsequent analyses typically take several sols, and freshly-exposed hydrated minerals may dehydrate between abrasion patch creation and their analyses, possibly resulting in an underestimation of the hydration state of subsurface materials.

Given what we know about hydrated minerals in Jezero crater and the laboratory results thus far, we hypothesized that rapid dehydration (within 24 hr) might occur to some hydrated minerals in abrasion patches after exposure to the current Mars environment in Jezero crater (Connell, Applin, et al., 2025). To investigate this, SuperCam (Maurice et al., 2021; Wiens et al., 2020) performed an in situ dehydration experiment in the SBM abrasion patch at the contact adjacent to the Bright Angel formation (Figure 1). The experiment involved a series of SuperCam observations over four sols, beginning shortly after abrasion, to measure possible changes in water-associated absorption bands of hydrated minerals. Performing SuperCam measurements shortly after abrasion was essential to this experiment, as hydrated minerals could dehydrate within hours of exposure at the surface before *Perseverance* instruments typically make their first measurements (Connell, Wiens, et al., 2025).
## 3. Methods

### 3.1. Perseverance Rover Instruments, Operations, and Processing

#### 3.1.1. SuperCam

SuperCam is a multi-technique remote-sensing instrument that includes active and passive methods. For Laser-Induced Breakdown Spectroscopy (LIBS), a 1,064 nm pulsed laser beam is used to ablate material and initiate a microplasma from 170 to 470 µm spot sizes (Maurice et al., 2021). Spectral analysis of the plasma emission (245–850 nm) provides elemental chemistry of the sample. Visible-infrared (VISIR) reflectance has a wavelength range of 0.40–0.85 µm and 1.30–2.60 µm. The field of view (FOV) of the visible range is 0.8 mrad, and the infrared is 1.15 mrad. The 532 nm remote time-resolved Raman and luminescence FOV is 0.8 mrad. Both VISIR and Raman-Luminescence spectroscopies are used to characterize mineralogy at mm scales (Anderson et al., 2022; Fouchet et al., 2022; Maurice et al., 2021; Wiens et al., 2020). A remote micro-imager (RMI) provides high-resolution color context imaging (FOV 18.8 mrad and resolution of <80 µrad) to document spectral analyses and rock textures (Maurice et al., 2021). SuperCam observations encompass a variety of observation types, ranging from a 3 × 3 grid pattern (utilized in this study) to a 10 × 1 raster (a row of 10 points).

SuperCam is unique among surface-based spectroscopic instruments as it includes an infrared wavelength range suitable for detecting water-bearing minerals. The infrared spectral region can be used to calculate band depths for hydrated minerals on Mars using the ~1.92–1.94 µm H₂O absorption band. Thus, band depth calculations were applied to atmospherically corrected data to measure any changes in water-associated spectral features (Clark & Roush, 1984; Viviano et al., 2014) in the SBM abrasion patch after exposure to martian surface conditions.

Band depth (BD) estimates are calculated using the following equation:

$$BD = 1 - \frac{R_c}{aR_s + bR_l}$$

Where c, s, and l correspond to the reflectance at center (R1930 or R1920), left–short–shoulder (R1845), and right–long–shoulder (R2151 or R2180) wavelengths, respectively, and Rₓ, a and b are the weighting coefficients calculated:

$$a = 1 - b \text{ and } b = \frac{\lambda_c - \lambda_s}{\lambda_l - \lambda_s}$$

to estimate the continuum above band center (e.g., Viviano et al., 2014).

Furthermore, similar phase angles were used over the course of our experiment to minimize photometric effects on band depth, so that band depth variation is associated with hydration only.

#### 3.1.2. SHERLOC (Scanning Habitable Environments With Raman and Luminescence for Organics and Chemicals)

SHERLOC is mounted on the rover's robotic arm and consists of two separate optical systems. One is the Wide Angle Topographic Sensor for Operations and eNngineering (WATSON) camera, which is a color imager used at working distances of ~1.8 cm to infinity. WATSON has a spatial resolution ranging from approximately 20–100 µm/pixel for working distances associated with proximity science (a few centimeters to tens of centimeters; Bhartia et al., 2021). The other is a deep UV fluorescence and Raman mapping spectrometer coupled to a co-boresighted Autofocus Context Imager, a grayscale microscopic imager with 10.1 µm/pixel resolution, which is used for focusing the spectrometer and providing textural context for the spectral maps.

The SHERLOC spectrometer uses a 248.6 nm NeCu deep UV pulsed scanning laser, with a spot size of 100 µm, to induce Raman scatter (810–4,000 cm⁻¹) and fluorescence emission (274–365 nm), and a single CCD (charge-coupled device) to detect both spectral phenomena simultaneously. This allows SHERLOC to produce spatially and spectrally resolved data from the abraded martian surface. Although the SHERLOC instrument has a variety of possible operational parameters, this study focused on one primary scan type, the Detail Scan. The Detail Scan was collected using 900 pulses per point within a 10 × 10 raster map (1 × 1 mm area). Due to an earlier dust cover
<caption>**Table 1**</caption>

Observation Parameters for Each Sol for All 3 × 3 Grid Measurements on the Steamboat Mountain Abrasion Patch

<table><thead><tr><th>Cadence</th><th>Target ID</th><th>Sol number</th><th>Time of day (LMST)</th><th>Cumulative time since abrasion</th><th>Phase angle</th><th>Technique</th></tr></thead><tbody><tr><td>Part 1</td><td>scam00191</td><td>1191</td><td>12:45</td><td>0:22</td><td>45°</td><td>R V I</td></tr><tr><td>Part 2</td><td>scam05192</td><td>1192</td><td>12:27</td><td>24:03</td><td>46°</td><td>R V I</td></tr><tr><td>Part 3</td><td>scam00193</td><td>1193</td><td>12:44</td><td>48:20</td><td>45°</td><td>R V I</td></tr><tr><td>Part 4</td><td>scam01195</td><td>1195</td><td>9:51</td><td>93:28</td><td>54°</td><td>L R V I</td></tr></tbody></table>

*Note.* SuperCam techniques: R = Raman, V = VISIR, I = RMI, L = LIBS.

anomaly, the SBM measurement was collected at a systematic focus offset of approximately 1.9 mm, increasing the target's laser beam size at the surface from the standard ~100 to ~275 µm, which attenuates the received signal and slightly broadens observed peaks. The data were initially studied using the software package Loupe (Uckert, 2022) to select spectra to average. The selected spectra were then exported to Excel, averaged, and normalized. A trimmed average of 2% of the selected spectra was used to remove cosmic rays.

### 3.1.3. MEDA (Mars Environmental Dynamics Analyzer)

MEDA consists of a series of sensors to monitor current martian environmental conditions near the surface and bulk aerosol properties (Rodriguez-Manfredi et al., 2021). These meteorological sensors are used to measure wind speed and direction, surface atmospheric pressure, RH at 1.45 m, atmospheric temperature (~1.5 and 0.5 m above the surface), downwelling (atmospheric) and upwelling (surface) thermal infrared fluxes, and brightness surface temperature (Rodriguez-Manfredi et al., 2021). In addition, a radiation and dust sensor (RDS) is used to monitor downwelling solar fluxes at different wavelengths from which bulk aerosol particle physical characteristics, distribution, and abundance can be derived (Rodriguez-Manfredi et al., 2021).

Specific MEDA data used in this work include surface atmospheric pressure, air and ground values for both RH and temperature, as well as solar fluxes to constrain the environmental conditions in which the SuperCam dehydration experiment was located. Regarding temperature, MEDA's ground temperature sensor (Martínez et al., 2023) is fixed on the rover's sensing mast, positioned 75° clockwise in the horizontal plane with respect to the Z-axis local frame. It is oriented downward at an angle of 35°, covering an ellipsoid area of about 4 m², which, in this case, does not overlap with the SBM abrasion patch but can serve as a proxy for it.

## 3.2. Dehydration Experimental Setup at Bright Angel

The dehydration experiment on SBM using the SuperCam instrument aimed to measure the progressive dehydration of hydrous minerals to characterize the initial hydration state in an abrasion patch on Mars. The abrading process on the natural rock surface of the Fern Glen Rapids member began at 12:07 and ended at 12:24 local mean solar time (LMST; 12:54 Local True Solar Time) on sol 1191. After the abrading process, the surface was cleared using the gDRT to remove any remaining dust particles from the abraded surface. This was followed by four SuperCam 3 × 3 grid observations on the same locations within SBM on sols 1191–1195 (Table 1) at a distance of 2.3 m. The first SuperCam measurement started at 12:45 LMST, just 22 min post-abrasion versus the nominal 44+ hours that SuperCam typically waits before characterizing minerals in abrasion patches. Although this was the shortest achievable time that SuperCam could make its first measurement post-abrasion, we acknowledge that dehydration could have occurred during the abrading process, as well as the 22 min gap between the completion of the abrasion patch and the initial measurement (Cloutis et al., 2008; Poitras et al., 2018; Valantinas et al., 2025). The cumulative time elapsed post-abrasion for each observation is given in Table 1.

The first three measurements involved SuperCam's VISIR reflectance spectroscopy and 532 nm pulsed Raman spectroscopy to characterize the mineralogy (Fouchet et al., 2022; Maurice et al., 2021; Wiens et al., 2020). The fourth observation involved all techniques, which included LIBS to characterize the geochemistry (Anderson et al., 2022), along with VISIR and 532 nm Raman spectroscopy. The LIBS was executed on the last sol to avoid any potential surface alteration caused by the laser. The SHERLOC deep ultraviolet (DUV) Raman spectrometer was also used to characterize the hydration phase of minerals in the SBM abrasion patch in different locations
(Bhartia et al., 2021; Murphy et al., 2025). To preserve the hydration state throughout the experimental area observed by SuperCam, we avoided overlapping it with SHERLOC and PIXL's observation areas. The SuperCam observations were made at solar zenith angles of ~45° for Parts 1–3 and 54° for Part 4 (Table 1), intentionally maintaining a nearly constant sun angle for VISIR observations. This was done to avoid spectral differences associated with variations in phase angle. For each infrared spectrum (IRS) obtained, band depths were calculated in the 1.93 µm H₂O region as described in Section 3.1.1. to identify adsorbed and/or absorbed water loss, that is, bulk dehydration (Viviano et al., 2014).

The choice of the rover workspace at the Fern Glen Rapids member (part of the Beaver Falls outcrop) for this experiment was not based on mineralogy but on the presence of the water absorption band (~1.93 µm) observed on the natural rock surface (before abrasion), and primarily the opportunity to perform the experiment as soon as it was approved and planned by the Mars 2020 Project. Based on rover resources, power, and time constraints, the rover was restricted from performing frequent dehydration experiments or ones of similar durations to those performed in the laboratory, where such experiments can occur over several months.

### 3.3. Grain Size Analysis

The grain size distribution and sphericity were calculated for the region of SBM shown in Figure 2, using ImageJ 1.54d (Rasband, W. S., ImageJ, U.S. National Institutes of Health, Bethesda, Maryland, USA, https://imagej.net/ij/, 1997–2018). First, a Gaussian stretch is applied to the Red-Green-Blue (RGB) RMI cropped image to emphasize grain boundaries and color. Then, a 2 × 2 mm grid is applied as a guide for which grains are measured to minimize bias toward measuring larger grains (e.g., Garefalakis et al., 2023). The large abundance of high albedo white patches in the image caused overexposure in certain areas, which likely impacted the identification of grain boundaries used for the textural analysis. As such, the grain size results are likely underestimated. Using the polygon tool, 200-grain outlines (yellow boundaries in Figure 2b) are drawn on the Gaussian stretched image while referring to the unstretched RGB RMI image, and their measurements are calculated using the fit ellipse function. The long axes of grains are measured and reported on in the grain size distribution, as these are considered the most accurate grain measurements in image analysis of a sedimentary outcrop (Garefalakis et al., 2023). Roundness was calculated from the polygons using ImageJ according to this equation 4*area/($\pi*major\ axis^2$). The RMI image resolution for the SBM target is 22.6 µm/pixel. At least five pixels are required to detect a grain, which results in grains finer than ~115 µm, for example, fine to very fine sand, not resolvable in the SuperCam RMI.

## 4. Results

### 4.1. Textural Analysis of Steamboat Mountain

Using natural color and Gaussian stretch context imaging, a textural analysis of the SBM abrasion patch (sol 1195) was done to investigate the relationship between grain size and composition. The texture of SBM (Figure 2a) indicates a moderately sorted sandstone consisting of coarse light green to dark green, translucent, olivine sand grains rimmed with light-toned sulfates, whose elemental composition is characterized and discussed below in Section 4.2.1. The fracturing of the olivine and replacement by sulfates can be seen better in Figure 2b (see Figure S2a in Supporting Information S1 for more detail). Some of the olivine grains are surrounded by a reddish-brown matrix whose grain size is too fine to resolve with SuperCam. In both the fine-grained matrix and translucent, green olivine grains, small, dull black grains are present that may represent iron-rich nodules or alteration of the olivine (Figure 2b). Figures S1 and S2 in the Supporting Information S1 provide further details about grain size, shape, and distribution. The RMI images were also used to ensure that, after abrasion, no dust accumulation and/or mobilization occurred during the experimental run.

The SBM abrasion patch's heterogeneity and coarser grain size indicate that clay-like lithology does not dominate the mineralogy. In the following sections, data from various rover instruments indicate the lack of clays/phyllosilicates and the relatively ubiquitous presence of olivine, Ca-sulfates, and Fe-hydroxides.
<figure><img src="image_5.png" /><figcaption>**Figure 2.** (a) Sol 1195 RGB Gaussian stretch fused remote micro-imager (RMI) mosaic of the SBM abrasion patch with a yellow box that indicates the region of interest for the textural analysis, shown in panel (b). Outside the yellow box in panel (a) is the circular edge of the abrasion patch at the bottom of the RMI frame. (b) Red and yellow boxes highlight different regions with apparent fracturing of the olivine and replacement by sulfates (white material). Small black grains and altered olivine grains are present in the fine-grained matrix, and possible nodules are shown in the blue box. The small black annotations over grain centers are numbered data points indicating their location on the map. The overlain grid was used to help randomize grain counting for measurement to avoid bias.</figcaption></figure>

## 4.2. SuperCam Spectral Data

### 4.2.1. LIBS and Time-Resolved 532 nm Raman Spectroscopy

LIBS characterized the geochemistry of the SBM abrasion patch on sol 1195 (Part 4) and showed variable compositions. The Supporting Information S1 includes the quantitative elemental compositions (see Table S3) with each point's respective wt.% and totals for the eight major elements (SiO₂, TiO₂, Al₂O₃, FeO_T, MgO, CaO, Na₂O, K₂O). The overall geochemistry shows a mafic-ultramafic composition, likely from olivine, also seen in the 532 nm Raman (see Figure S4 in Supporting Information S1). Orthopyroxene is interpreted for most points, and two points with very low SiO₂ (~9–15 wt.%), and high FeO_T (40–59 wt.%) likely represent mixtures with Fe-(hydr)oxides. The data show relatively low Na₂O, K₂O, and TiO₂ except in point 6, elevated FeO_T in points 8 and 9, elevated MgO in points 2, 3, and 7, and elevated CaO in point 5 (Table S3 in Supporting Information S1). The ternary diagram (Figure 3a) shows points that plot near the olivine, pyroxene, and serpentine standards (mafic-ultramafic), with two points trending toward the Fe + Mg apex indicative of mixtures with Fe-oxides. Figure 3b shows the location of each LIBS point (3 × 3 grid) corresponding to the compositions indicated in the ternary diagram and Table S3 in Supporting Information S1.

While hydrogen emission lines are easily observed by LIBS, quantifying the H content from martian LIBS data is complicated, in particular due to matrix effects (Rapin et al., 2017; Schröder et al., 2015). However, a spectral unmixing score can serve as a proxy (Hansen, 2022; Schröder et al., 2023). SBM's LIBS semiquantitative hydrogen (H) spectral unmixing scores were plotted as a function of sol number along with other abrasion patches along the rover traverse (Figure 3c). The data show that SBM generally has lower H scores than some points observed in other abraded targets in Jezero crater (Figure 3c). The SuperCam 532 nm Raman spectroscopy, which also characterized minerals in the abrasion patch, gave inconclusive hydration results due to a lack of peaks associated with the O-H stretching band (~3,200–3,400 cm⁻¹; see Figure S4 in Supporting Information S1) however, O-H associated peaks were observed with the SHERLOC DUV Raman (see Section 4.3).

### 4.2.2. Infrared Spectroscopy (IRS)

SuperCam observations were targeted at the same coordinates on the SBM abrasion patch on four consecutive sols (1191–1195) to characterize the hydration state and mineralogy. Figure 4 shows spectra from all nine IRS points for each sol. All spectra exhibit a 1.93 µm H₂O absorption band, and some points show a very weak 1.43 µm OH (hydroxyl) band. Very weak 2.31 µm bands are also observed in the metal-OH region (e.g., OH
<figure><img src="image_6.png" /><figcaption>**Figure 3.** (a) Ternary diagram of the SBM abrasion patch showing all nine Laser-Induced Breakdown Spectroscopy (LIBS) points (color bar = raster point), indicating diversity in geochemistry (plotted over LIBS compositions up to sol 1347). (b) Natural color RGB remote micro-imager image with cross hairs showing the locations of the LIBS points. (c) H spectral unmixing scores of LIBS observation points throughout the rover traverse, highlighted in different colors showing the SBM abrasion patch in comparison to other abrasions.</figcaption></figure>

combination bands), which are indicative of carbonate or Mg/Fe phyllosilicates (Bishop et al., 2008). However, SuperCam does not exhibit clear paired diagnostic 2.30 and 2.50 µm absorption bands, associated with overtones and combinations of the fundamental CO₃ bending and stretching modes (Gaffey, 1987; Harner & Gilmore, 2015) that are typically used for identifying carbonates. Thus, the absence of the paired carbonate absorption bands suggests a limited or ambiguous presence of carbonates.

PIXL interpreted particulate and intragranular Fe/Mg carbonate in another area of the SBM abrasion patch (Hurowitz et al., 2025), in contrast to the lack of strong carbonate bands in the SuperCam data. However, SuperCam may not have detected strong carbonate signatures due to mineral mixing within the larger IRS FOV (e.g., 2,640 µm) than PIXL's smaller X-ray fluorescence laser beam size (e.g., ~120 µm; Hurowitz et al., 2025). Alternatively, other minerals (e.g., sulfates) could be masking the presence of carbonates, resulting in weaker absorption bands, or perhaps carbonates are simply not present in the location analyzed by SuperCam. Moreover, the 2.31 µm Fe-OH band could instead be associated with phyllosilicate minerals, including species that lack H₂O-bound water and only contain structural OH, consistent with hydroxyl-bearing phyllosilicates.

A steep positive Fe²⁺ slope between 1.30–1.80 µm (Figure 4) is present, consistent with olivine. This slope arises from the contribution of a broad Fe²⁺ crystal field absorption, which can also result in obscuring the 1.43 µm OH band (Mandon et al., 2022). The mineral associated with this band is likely olivine, which is supported by SuperCam's 532 nm Raman and the LIBS data, indicating that olivine is the main contributor to the Fe²⁺ slope
<figure><img src="image_7.png" /><figcaption>**Figure 4.** IRS spectra for sols 1191–1195 at a 1.30–2.60 µm wavelength range. All IRS points show a steep/red Fe²⁺ slope from 1.30 to 1.80 µm, a 1.93 µm (H₂O) band, and very weak 1.43 µm (OH) and 2.31 µm (Fe-OH/Mg-OH) absorption bands, and a negative slope longward of 2.40 µm.</figcaption></figure>

rather than Fe-carbonate, which can also exhibit this type of spectral slope. Additionally, the VIS spectra exhibit peak reflectance values near 670 nm, which is also consistent with olivine-bearing materials (see Figure S5 in Supporting Information S1). Moreover, PIXL also interpreted coarse crystalline granules of olivine in another location (Hurowitz et al., 2025). Lastly, at longer wavelengths, the spectra show a 2.40 µm downward slope, consistent with the possible presence of sulfate (Quantin-Nataf et al., 2024).

The main mineral phases present in the SuperCam data are olivine as seen in the LIBS, Raman and VISIR, and likely Fe-hydroxide based on the water band in the IRS in combination with the Fe-oxide detected by the LIBS. Overall, the SBM IRS spectra also resemble the spectral signature of ferrihydrite (Fe₂O₃·nH₂O) mixed with olivine (Figure 4; Dehouck et al., 2017). This is indicated by the 1.30 µm downturn toward shorter wavelengths
<figure><img src="image_8.png" /><figcaption>**Figure 5.** (a) RMIs for sols 1191–1195 showing the location of the overlapping SuperCam 3 × 3 grids with an IRS field of view (FOV) of 1.15 mrad (calculated FOV of 2.64 mm) in the SBM abrasion patch (perimeter of the abrasion shown at the edge of the frames). (b) Zoomed-in image of the IRS FOV locations for all sols, indicating offsets. Sols 1192 and 1193 have the closest correspondence (e.g., 0.2–0.18 mm); Sols 1191 and 1195 have larger offsets (e.g., 0.23–77 mm). See Table S6 in Supporting Information S1 for offset values associated with each point for all sols.</figcaption></figure>

caused by the typical crystal field absorption of the Fe²⁺ in the olivine band and the 1.90 µm H₂O band associated with H-O-H bonds in ferrihydrite (Dehouck et al., 2017), consistent with the IRS, which makes it a potential candidate. Moreover, other minerals such as Ca-sulfates likely contribute to the water band in combination with an Fe-oxyhydroxide, such as ferrihydrite. Due to the high sensitivity of reflectance spectroscopy to carbonates and phyllosilicates and the weak 2.31 µm band in the IRS, it is challenging to constrain the presence of these minerals in the SuperCam data, and they are likely minor phases in SBM if present. Thus, they are not considered major mineral phases in the SuperCam observations of the SBM abrasion patch.

Here, we focus on the best spectral comparisons, specifically between sols 1192 and 1193. This is due to the slight shifting of IRS points on other sols, as shown in Figure 5a, likely resulting from rover arm mobility and/or thermal effects on the rover hardware among various activities. Multiple mineral grains occupy the IRS FOVs, evident in Figure 5b; however, observations on sols 1192 and 1193 (Parts 2 and 3) are identical in most cases, whereas sols 1191 and 1195 are slightly more shifted (Parts 1 and 4). Thus, it is more useful to compare hydration for the IRS FOVs with nearly identical locations (sols 1192 and 1193) on the abrasion patch.

#### 4.2.2.1. Key Results for the Dehydration Experiment (IRS Band Depth Calculations)

Bulk hydration for sols 1192 and 1193 was estimated using the 1.93 µm H₂O absorption band associated with O-H stretching plus H-O-H bending (Figure 6). The goal was to estimate loss of adsorbed and/or absorbed water. The BD1930 band depths for each point show a minimum of 7.6% to a maximum of 12.3% for both sols. The 1.93 µm absorption bands were stable and showed no significant changes in band depth that were visually apparent, that rose above the instrument noise level, and/or showed changes in relative reflectance of >±2% (Connell, Applin, et al., 2025), as shown in the calculated BD1930 values. The longer wavelength wing of the 1.93 µm H₂O absorption band also showed no significant changes, suggesting no loss of adsorbed water. Minor dehydration and/or dehydroxylation may have occurred, but it did not rise to a level of significance that can be accurately observed. The small changes in the IRS FOV between points (e.g., point 1 on sol 1192 and point 1 on sol 1193) likely contributed to the slightly different band depth percentages (under 2%), as shown in the BD1930 values, likely from the incorporation of different mineral grains (Figure 5b) and/or instrument noise level. See Figures S7 and S8 in Supporting Information S1 for normalized and ratioed 1.30–2.60 µm spectra, as well as standard deviations and denoised spectra of the 1.93 µm H₂O band.

Although SBM's bulk hydration in the Bright Angel formation was stable during the experiment and showed relatively low hydration indicated by the H₂O band depths (Figure 6), other geological units in Jezero crater may
<figure><img src="image_9.png" /><figcaption>**Figure 6.** SuperCam IRS at a 1.30–2.60 µm wavelength range for sols 1192 (left) and 1193 (right). Band depth calculations (BD1930) of the 1.93 µm H₂O band were done for these sols over the same location in the SBM abrasion patch. The horizontal dashed lines connect the left and right shoulders, indicating the continuum. The left vertical line represents the band center used for the calculation, and the right vertical line at the longer wavelength wing indicates the region associated with adsorbed water.</figcaption></figure>

exhibit different responses in terms of bulk hydration stability. To address this, we compared the 1.93 µm band depth regions of the three abrasion patches (SBM, Apollo Temple, Walhalla Glades) in Bright Angel to other abrasion patches along the rover traverse, which is discussed in more detail in the following section. Making comparisons in hydration across various units will help us constrain the overall hydration state of Jezero crater and reveal where Bright Angel sits on the hydration state spectrum.

### 4.2.2.2. Abrasion Bulk Hydration Estimates in Jezero Crater

A summary of all SuperCam IRS abrasion hydration band depths is shown in Figure 7a. The figure includes averaged ~1.90 µm H₂O band depths of abrasion patches from various science campaigns along the rover traverse, such as the Crater Floor (e.g., Mandon et al., 2024), Delta Fan (fan front/fan top), and Margin Unit up to the crater rim contact (Figures 7a and 7b). The data shows variability in abrasion patch hydration states. The Delta Fan exhibits the highest hydration, with some H₂O band depths reaching as high as 20%, while the Crater Floor rocks display the lowest hydration, and the Margin Unit rocks show intermediate hydration. The gray points are pyroxene- and olivine-rich boulders (e.g., Beyssac et al., 2024; Poulet et al., 2024) and are not in place like the other abraded rocks; however, they were included because they were likely transported from flood deposits from the Jezero watershed or are associated with erosional lag of an overlying unit (Vaughan et al., 2025). Additionally, it should also be noted that each of the abrasion patch observations were taken at slightly different times of day, which may influence the depth of the 1.90 µm H₂O band, and that each point in the raster has a different hydration state, as demonstrated by the standard deviation error bars (Figure 7a). The 1.90 µm band was calculated using variable band positions associated with the maximum absorption after continuum removal between 1.85 and 2.11 µm. Furthermore, heterogeneity in the 2.45 µm band depths (calculated using a linear continuum approximation anchored at 2.15 µm) is also observed among the abrasion patches in all three science campaigns, generally trending with the 1.90 µm band depths. In this way, the Delta Fan (fan front/fan top) shows some of the highest 2.45 µm band depths, followed by the Margin Unit (Figure 7a).
<figure><img src="image_10.png" /><figcaption>**Figure 7.** (a) SuperCam hydration (1.90 µm H₂O) averaged band depths and 2.45 µm band depths of abrasion patches along the rover traverse, including the Crater Floor (yellow), the Delta Fan encompassing both the fan front and fan top (light blue), and the Margin Unit (purple) campaigns up to the crater rim contact. The error bars represent standard deviations from each raster. (b) A map of Jezero Crater showing the rover traverse (white) beginning from the Crater Floor, Delta Fan, Margin Unit up to the Crater Rim (blue dot rover position) up to sol 1429. The black location points represent abrasion patches. The orange star shows the location of the Bright Angel formation and the three abrasion patches described in panel (a). See Figure S9 in Supporting Information S1 for a list of abrasion patches and their respective science campaigns and sol numbers.</figcaption></figure>

The hydration state of the Bright Angel formation is indicated by the SBM, Apollo Temple, and Walhalla Glades abrasions (Figure 7a, orange stars). These abrasions indicate that bedrock in Bright Angel has some of the lowest hydration in Jezero crater, similar to the aqueously altered igneous units on the crater floor, such as Máaz and Séítah (Figures 7a and 7b). There are also evident differences in hydration between SBM, Apollo Temple, and Walhalla Glades. SBM alone has more substantial 1.90 µm H₂O band depths than Apollo Temple and Walhalla Glades (Figure 7a). SBM, Apollo Temple, and Walhalla Glades also show lower 2.45 µm band depths associated with mineral band assignments (Figure 7a) compared to the Delta Fan (fan front/fan top) and the Margin Unit. Overall, these data indicate that the experiment was conducted in an area of Jezero that holds less water than other units.

Aside from differences in hydration between the three Bright Angel abrasion patches, there are also distinct textural and mineralogical differences in Bright Angel, as described in Section 2.1. The Apollo Temple and
<figure><img src="image_11.png" /><figcaption>**Figure 8.** (a) SHERLOC 10 × 10 Detail Scan (900 pulses/point, 1 × 1 mm area) DUV Raman spectra from 850–4,000 cm⁻¹ on SBM showing mineral peaks associated with a mixture of bassanite and anhydrite, as well as some hydration on sol 1193 (labeled). (b) Autofocus Context Imager image showing the spectral map (red points) for the SHERLOC 10 × 10 Detail Scan. The yellow points represent anhydrite, and the blue points represent bassanite and anhydrite. See Figure S10 in Supporting Information S1 for the approximate locations of the SHERLOC and SuperCam observations.</figcaption></figure>

Walhalla Glades bedrock exhibit fine-grained, laminated light-toned rocks that are phyllosilicate and sulfate-rich and show lower hydration than the coarser-grained, poorly stratified, darker conglomerate dominated by olivine and Ca-sulfates seen in SBM. In fact, Ca-sulfates are seen throughout Bright Angel in the rock matrix and as localized veins or coarse detrital layers (possible strata-bound veins), and early nodular concretions as mostly anhydrite (Hurowitz et al., 2025; Mandon et al., 2025; Manrique et al., 2025). The variability in hydration between Apollo Temple and Walhalla Glades versus SBM is almost certainly associated with mineralogical, textural, and structural differences, including mineral distribution (homogeneous vs. heterogeneous) and grain size. There is an overall linear decrease in hydration from the SBM abrasion (northern Margin Unit contact) to Apollo Temple and Walhalla Glades south of Bright Angel (see map in Figure 1b).

As mentioned, SuperCam IRS measures bulk hydration, as there are usually multiple minerals in each observational footprint. SHERLOC DUV Raman, however, can constrain the mineral hydration phases and associated cations shown in the next section; thus, SHERLOC data are needed to enable mineral assignments.

## 4.3. SHERLOC DUV Raman

The SHERLOC data (Figure 8) show spectra selected over the light-toned grains in the SBM abraded patch from sol 1193. Five light-toned points show hydration at 3,555 cm⁻¹, while most others had no water. The data indicates the presence of Ca-sulfates (~1,012, 1,130, 1,160, 3,555 cm⁻¹), showing a mixture of bassanite (CaSO₄·0.5H₂O) and anhydrite (CaSO₄; Figure 8). The presence of bassanite and anhydrite, and the absence of gypsum (CaSO₄·2H₂O), suggests that these phases have already undergone a significant degree of dehydration or were precipitated as these respective phases.

## 4.4. MEDA (Mars Environmental Dynamics Analyzer)

As discussed in Section 1.1, hydrated minerals are sensitive to the current martian environment, and the observed environmental factors have been used as controls for various Mars chamber experiments conducted in the laboratory. To understand the Mars environment, we used MEDA to record the pressure, temperature, RH, and UV radiation flux over the course of the experiment (sols 1190–1194), which are described in this section.

Figure 9a shows a Navcam mosaic from sol 1191 with MEDA's FOV for the ground temperature sensor (green shaded area) and the SBM abrasion patch (blue arrow; see Section 3). The area over which the ground temperature was read was within 3 m of the abrasion patch. Figure 9b shows MEDA measurements of surface and air (1.45 m above ground level) temperatures and simulated UV fluxes in the 190–400 nm range during sols 1190–1194. While MEDA's Radiation and Dust Sensor measured incoming solar radiative fluxes during this period, two factors significantly affected its readings. First, due to the RDS's location on the rover deck and the ~12° terrain slope, the sensor experienced a significant tilt, leading to substantially higher measurements than expected on a
<figure><img src="image_12.png" /><figcaption>**Figure 9.** (a) Navcam mosaic from sol 1191 showing MEDA's ground temperature sensor field of view (green shaded area) and the SBM abrasion patch (blue arrow), (b) MEDA measurements of ground (blue) and air (red) temperatures, and simulated UV flux (green) in the 190–400 nm range during sols 1190–1194 corresponding to the Bright Angel region. The UV fluxes were simulated on a horizontal surface from the COMIMART radiative transfer model, using Mastcam-Z opacities, (c) simulated surface RH with (green) and without (blue) considering adsorption ("ads") onto the regolith, and MEDA measurements of air RH (red). The dashed vertical lines in panels (a, b) indicate the approximate times of the SuperCam (~9:00 and 12:00) and SHERLOC (~20:00) observations.</figcaption></figure>

horizontal surface. Second, the RDS is affected by dust accumulation (Vicente-Retortillo et al., 2024), and measurements are lower than the actual flux on the surface. To account for these effects, we simulated UV fluxes using the radiative transfer model COMIMART (Vicente-Retortillo et al., 2015) fed with Mastcam-Z opacities (Lemmon et al., 2022). When correcting for dust accumulation and rover tilt, the simulated UV fluxes are in excellent agreement with MEDA RDS measurements. During the SuperCam experiment, the UV radiation fluxes peaked at ~32 W/m² (Figure 9b).

Figure 9c shows MEDA measurements of RH in the air at 1.45 m, along with simulated surface RH values with and without accounting for adsorption onto the regolith. Over the last decade, it has been shown to be the key role played by the surface-atmosphere exchange of H₂O in the local water cycle (Rivera-Valentín et al., 2021). More specifically, in situ measurements of RH in the air by the Phoenix, MSL, and Mars 2020 missions can only be realistically simulated by a model when adsorptive processes are accounted for (e.g., Savijärvi et al., 2020; Savijärvi et al., 2024). We used the University of Helsinki/Finnish Meteorological Institute Single Column Model (SCM) to simulate surface RH values incorporating adsorption. The SCM includes regolith-atmosphere H₂O exchange through a validated scheme presented in Savijärvi et al. (2020). The SCM was initialized with a dust opacity value of 0.8 measured by Mastcam-Z, a daily mean surface pressure of 768 Pa measured by MEDA, and a water column abundance of 10 µm-pr retrieved from the Mars InfraRed Spectrometer (EMIRS). Additionally, estimated values for thermal inertia (375 SI units), albedo (0.17), and porosity (0.23) were used to optimize the model's fit to the measured ground temperature and nighttime volume mixing ratio at 1.45 m. Surface RH values without adsorption were derived by assuming a constant water vapor profile within the first 1.45 m and using MEDA ground temperature measurements. Notably, adsorption significantly reduces the maximum daily surface RH values from approximately 60%–16%.

Table 2 summarizes the above-mentioned MEDA-determined atmospheric conditions at the time of each SuperCam observation on SBM. Ground RH is effectively 0% because the values fall below the lower detection limit of 2%, within the uncertainty of zero (Polkko et al., 2023). Furthermore, during the SHERLOC observation
<caption>**Table 2**</caption>

Atmospheric Values of Ground Temperature, UV Flux, and RH at the Time of the SuperCam Measurements

<table><thead><tr><th>Cadence</th><th>Target ID</th><th>Sol number</th><th>Time of day (LMST)</th><th>Temperature (K)</th><th>UV flux (190–400 nm) W/m<sup>2</sup></th><th>RH %</th></tr></thead><tbody><tr><td>Part 1</td><td>scam00191</td><td>1191</td><td>12:45</td><td>263</td><td>32</td><td>0</td></tr><tr><td>Part 2</td><td>scam05192</td><td>1192</td><td>12:27</td><td>263</td><td>32</td><td>0</td></tr><tr><td>Part 3</td><td>scam00193</td><td>1193</td><td>12:44</td><td>263</td><td>32</td><td>0</td></tr><tr><td>Part 4</td><td>scam01195</td><td>1195</td><td>9:51</td><td>241</td><td>24</td><td>0</td></tr></tbody></table>

*Note.* The daily mean Mars surface pressure for all measurements is ~768 Pa.

(Sol 1193), well after sunset (20:00 LMST), the air temperature was approximately –60°C and humidity ranged from 2% to 5%.

# 5. Discussion

## 5.1. Jezero Crater Bulk Hydration State

The Bright Angel formation is generally weaker in hydration than other locations in Jezero crater, such as the Delta Fan (fan front/fan top) and most targets in the Margin Unit, and is more consistent with the Crater Floor. The abrasion patches in Bright Angel share similar hydration states to that of aqueously altered igneous rocks, as seen in the Máaz and Séítah formations (Figure 7a). There are several possible reasons for lower hydration observed in Bright Angel that could be correlated with OH-bearing (hydroxyl) rather than H₂O-bearing phyllosilicates, and the presence of low-water Ca-sulfate phases. As for the SBM abrasion of the Fern Glen Rapids member, distinct from the rest of Bright Angel (at the northern Margin Unit contact), the main hydration phases are likely Fe-hydroxides and Ca-sulfates. The dominant mineral is olivine, which is anhydrous, and there are possible trace minerals such as other Fe-oxides, Fe/Mg carbonate, and/or Mg/Fe phyllosilicates. Moreover, this mineralogy is similar to that of the crater floor.

The hydration and lithological differences between the Fern Glen Rapids member and the rest of Bright Angel (e.g., Cheyava Falls and Walhalla Glades) are likely due to the Fern Glen Rapids' location at the contact between the northern Margin Unit and Bright Angel lithologies. This is evidenced by not only the transition from coarse-grained dark to fined-grained light-toned materials (Figure 1c), but also the linear decrease in water band intensities from the more hydrated Margin Unit to the lesser hydrated area south of Bright Angel, such as the Walhalla Glades abrasion patch (Figure 7a). However, it is critical to note that there are multiple working hypotheses to explain the formation of Bright Angel, based on the various hydration, textural, and mineralogical characteristics. For example, two possible models for the deposition of Bright Angel are that it is either a younger, channel-filling unit, post-dating the Neretva Vallis incision, or it underlies and pre-dates the Margin Unit and has been exposed by the Neretva Vallis incision (Barnes et al., 2025). However, it is apparent that hydration is strongly linked to different lithologies and likely represents differences in mineralogy.

## 5.2. Stability of Minerals in the Steamboat Mountain Abrasion Patch

The SuperCam spectra for SBM for sols 1192 and 1193 (Parts 2 and 3) did not show any significant changes in hydration of the 1.93 µm H₂O absorption band over the 25-hr and 26-min interval between these observations (Figure 6). We also examined the long-wavelength wing of the 1.93 µm band, as this portion of the band is indicative of adsorbed water that is likely mobile on Mars due to atmospheric-surface interactions of loosely bound water in or on various minerals (Connell, Applin, et al., 2025; Poitras et al., 2018; Turenne et al., 2022). Overall, there are no changes in band depth that were visually apparent, that rose above the instrument noise level, and/or showed changes in relative reflectance of >±2% (Connell, Applin, et al., 2025) for any of the observations starting 22 min after the abrasion on sol 1191 and continuing to the sol 1195 observation (Figure 4).

SuperCam and SHERLOC data indicate that water-bearing Fe-hydroxides and Ca-sulfates are likely the primary carriers for hydration (OH/H₂O), with the potential for minor OH contributions from phyllosilicates. SHERLOC indicates that hydration is spatially variable across the abrasion, showing areas with varying degrees of hydration in Ca-sulfates. Thus, SHERLOC classified the Ca-sulfates as a mixture of bassanite and anhydrite (Figure 8), suggesting that possible partial dehydration already occurred in the subsurface materials of the abrasion patch.
However, an alternative is that the Ca-sulfates could have also initially precipitated in a lower hydration phase on Mars (e.g., as bassanite first instead of gypsum; Stawski et al., 2020).

The variable hydration in Ca-sulfates in SBM could be explained by rover instrument observations and previous laboratory studies that examined the stability of Ca-sulfates. Vaniman et al. (2024) showed that dehydration of gypsum at Mars equatorial surface conditions can occur over 5–38 sols in the samples they measured with the CheMin (X-ray diffraction), ChemCam (LIBS), and APXS (Alpha Particle X-ray Spectrometer) instruments on NASA's *Curiosity* rover in Gale crater. Their measurements demonstrated how Ca-sulfates, such as gypsum, can be unstable (e.g., dehydrate) under these conditions (Vaniman et al., 2024). This is also supported by previous laboratory work (Cloutis et al., 2008; Poitras et al., 2018), where gypsum was measured under warm, Mars equatorial-like surface conditions (e.g., ~600–930 Pa, CO₂ atmosphere at ambient temperature) in the laboratory and did not immediately dehydrate, but only dehydrated after extended exposure (e.g., several weeks) or from a reduction in atmospheric pressure to below that of Mars. However, it is important to note that sulfates are sensitive to RH and temperature, which will drive stability at different rates (Wang et al., 2009).

Vaniman et al. (2018) also demonstrate that additional factors, including grain crystal size, habit, rock fabric, and other petrologic variables, can influence the dehydration rates of gypsum at equatorial latitudes on Mars. As such, exposed subsurface gypsum will likely slowly dehydrate to bassanite. At Jezero crater, *Perseverance* also measures samples at a near-equatorial site (18°N), and the Ca-sulfates measured have been predominantly in a lower hydration state (anhydrite and bassanite) as seen with rover instruments (e.g., Phua et al., 2024; Siljeström et al., 2024). Thus, the sulfates in Jezero have been observed at variable hydration states. Moreover, the Supporting Information S1 (Text S11) describes additional details about sulfate hydration phases in Jezero crater along the rover traverse. In this work, we did not observe evidence of bassanite fully dehydrated to anhydrite, which could be explained by the slow kinetics of dehydration from gypsum to bassanite, as observed in previous Mars chamber experiments showing gradual changes in the 1.90 µm H₂O band depth (Poitras et al., 2018). This may suggest that more exposure time would be required beyond the four sols during which the Mars measurements took place to detect observable phase transitions from bassanite to anhydrite.

Aside from Ca-sulfates, Fe-hydroxide in the form of ferrihydrite is an additional mineral species that potentially contributed to the hydration state of SBM. However, whether the 1.93 µm band is solely from the presence of hydrated Ca-sulfates or ferrihydrite (or other hydrated mineral species) is unclear, as the band is likely a combination of both. This is based on the portion of the RMI image within the IRS FOV, which showed lighter and darker grains in a reddish-brown matrix (Figure 5b), interpreted as a mixture of minerals. Moreover, light-toned grains dominate the IRS FOV, suggesting that the Ca-sulfates likely contribute the most to the water band. Other Fe-oxide minerals could also be present, such as crystalline phases like goethite and hematite, of which goethite is a hydroxyl-bearing phase only. Furthermore, hydration is consistently observed throughout the SuperCam points, even in areas dominated by the reddish-brown matrix, which is consistent with ferrihydrite's water-bearing composition, but there could be a mix of different Fe-hydroxides. However, PIXL interpreted the ferric red matrix in the SBM abrasion patch as finely crystalline to amorphous, consistent with ferrihydrite's poor crystalline structure (Hurowitz et al., 2025). Additionally, the SuperCam, VIS wavelength spectra of the reddish-brown matrix material show peak reflectance positions near 735 nm, strong downturn toward longer wavelengths, and an enhanced 545 nm (ferric) band depth, suggestive of mixtures of Fe-oxides/oxyhydroxides (see Figure S12 in Supporting Information S1).

Valantinas et al. (2025) investigated poorly crystalline ferrihydrite under Mars-like surface conditions at warm, equatorial-like temperatures (e.g., ~500–700 Pa, CO₂ atmosphere at 22°C, ±UV irradiation). They demonstrated that ferrihydrite undergoes rapid dehydration (after several minutes) of adsorbed water but does not transition into a more crystalline Fe-oxide phase (Valantinas et al., 2025). This suggests that the Fe-hydroxide (ferrihydrite) in the abrasion patch would remain poorly crystalline on Mars, even if dehydrated. However, it is critical to note that the ferrihydrite experiment was done at terrestrial ambient temperatures (Valantinas et al., 2025); hence, the warmer temperature is likely the main driver of dehydration during the experiment, whereas the SBM experiment on Mars was done at temperatures well below 0°C.

It is apparent that the SBM abrasion mineralogy does include minor phases known to show instability on Mars (e.g., Fe-hydroxides and Ca-sulfates); however, those minerals may no longer dehydrate as they have already lost water, potentially reaching equilibrium, as evidenced by Bright Angel's already lower hydration state. Another possibility is that minerals without bound water but containing hydroxyls could be present, evidenced by the very
weak absorption bands centered at 1.43 and 2.31 µm. These hydroxyl-bearing minerals would likely remain stable on Mars, as hydroxyl absorption bands are generally stable under current Mars environment conditions (Cloutis et al., 2007, 2008; Connell, Applin, et al., 2025; Poitras et al., 2018; Turenne et al., 2022). Furthermore, if a minor mineral phase did dehydrate, the spectra may not show a substantial decrease in band depth if the mineral mixture is dominated by stable phases that show no dehydration or gradual dehydration (Connell, Applin, et al., 2025; Poitras et al., 2018). Therefore, hydration bands may not exhibit significant spectral changes if higher stability hydrous minerals create a localized micro-RH environment (e.g., within pore spaces between mineral grains), effectively buffering adjacent minerals and maintaining a local hydrated and stable environment (Wang et al., 2009). Lastly, slow dehydration kinetics could predominate based on the ranges of temperature and RH associated with the martian seasons, as the SuperCam measurements were taken in the winter, with maximum temperatures remaining below 270 K (Figure 9). Therefore, a different outcome might have been observed if the experiment had been conducted under warmer martian summer temperatures.

### 5.3. Environmental Conditions in Jezero Crater

We used MEDA to record the martian environmental conditions over the course of the SuperCam dehydration experiment on the SBM abrasion patch. Here, we will focus on the environmental parameters when the SuperCam hydration measurements were made, which occurred at a daily mean surface pressure of 768 Pa, consisting of martian winter surface temperatures of ~263 K (−10°C) and 241 K (−32°C; see Table 2 and Figure 9b). The cold temperatures observed on Mars likely make it challenging for loosely bound adsorbed water, if present, to be released from the minerals. The radiation flux during this time is highest throughout the first three measurements, reaching ~32 W/m² and lower for the fourth measurement at ~24 W/m² (Figure 9b), but is not expected to affect surface hydration at these lower values. The RH was very low for all SuperCam measurements at effectively 0% (Figure 9c), indicating that observations were made during the driest time of day (Savijärvi et al., 2024; Zorzano et al., 2024).

Despite RH varying throughout the sol, from nearly 0% to as high as 60% (Figure 9c), no change was observed in the hydration state of the abrasion patch minerals. This suggests that exposure to daily martian environmental conditions did not result in surface dehydration or rehydration based on what we observed. The stability of these freshly abraded minerals is likely due to the composition of the SBM abrasion patch and low surface temperatures. However, previous laboratory studies demonstrated that water content in some minerals can vary across diurnal martian temperature cycles, depending on partial pressure of H₂O and temperature (Bish et al., 2003). In contrast, the SBM abrasion patch did not exhibit such variations, implying limited exchange with the atmosphere during the time frame of this experiment.

### 5.4. Future Dehydration Experiments on Mars

The Fern Glen Rapids member was only moderately hydrated prior to abrasion (see Figure S13 in Supporting Information S1), and thus the dehydration experiment would be better suited to occur in areas with higher initial hydration and involving outcrops with minerals expected to be unstable under modern Mars environment conditions. These potential settings for the next experiment could ideally consist of hydrated Mg/Fe/Al-rich phyllosilicates rather than Fe-hydroxides and Ca-sulfates. SuperCam has identified many Fe/Mg-bearing phyllosilicates, including smectites, along the rover traverse on the crater floor and western fan (Dehouck et al., 2023; Mandon et al., 2023a, 2023b). Candidate minerals, such as smectites like hectorite, nontronite, montmorillonite, and saponite, are ideal due to their ability to hold up to >10 wt.% water, depending on the type of interlayer cations (Bish et al., 2003; Chipera et al., 1995), and could be found within the Noachian basement on and outside of the Jezero crater rim. In fact, a subsequent laboratory experiment was done on montmorillonite to measure how quickly adsorbed water was lost in the initial 24-hr time frame (see Figure S14 in Supporting Information S1). The data show changes in the long-wavelength wing of the 1.91 µm absorption feature within minutes of exposure to Mars-like surface conditions, indicative of adsorbed water loss. Other desirable candidates are kaolin-group minerals such as halloysite, which can contain up to 14 wt.% water and could be found in crater rim kaolinite-megabreccia blocks (Scheller et al., 2021). Lastly, hydrated silica, present in float rocks consistent with opal, has been discovered in Jezero crater (Beck et al., 2025), of which opal-CT and opal-A are also known to be unstable under current Mars surface conditions (Chauviré et al., 2021; Poitras et al., 2018).
### 5.5. Implications for Estimating the Global Mars Water Budget

Several generations of Mars orbiters and landed spacecraft have facilitated efforts to determine the martian water budget, including all possible sources and sinks. One of the major global water sinks is the formation of hydrated minerals themselves (Riu et al., 2023; Scheller et al., 2021). Global estimates of the martian water budget that rely on orbital and rover-based observations of dehydrated or dehydroxylated surfaces could lead to underestimates of the actual amount of water “locked” within ancient sedimentary rocks on Mars. In fact, results from laboratory Mars chamber studies suggest that surface observations may severely underestimate the water budget due to the instability of hydrous minerals when exposed to the modern Mars atmosphere (Cloutis et al., 2007, 2008; Connell, Applin, et al., 2025; Poitras et al., 2018; Turenne et al., 2022).

Hydrated minerals serve as a proxy for understanding past climates and environments, revealing key factors such as water chemistry, pH levels, wet and dry periods, surface temperature, and indirectly from these parameters, atmospheric pressure (Bishop, 2018; Hurowitz et al., 2006). Thus, a lack of understanding of the initial hydration states of minerals can lead to incorrect inferences about Mars' early climate and habitability. Although our results showed no significant dehydration or dehydroxylation, other orbital or rover-based observations of mineral hydration (e.g., MSL; Bristow et al., 2018; Fraeman et al., 2016), which are based on minerals known to be unstable (e.g., phyllosilicates), might be subject to comparably more dehydration. This could skew estimates of the bulk water content (in wt.% H₂O) and potentially further contribute to ongoing disagreements about the water budget on Mars (e.g., Audouard et al., 2014; Milliken et al., 2007).

To accurately estimate the martian water budget and better understand the planet's early climate and habitability, it is essential to conduct additional dehydration experiments on Mars using the SuperCam instrument on the *Perseverance* rover, particularly on minerals prone to dehydration in the current martian environment. Future experiments on more suitable mineral candidates in bedrock with higher bulk hydration will offer valuable insights into Mars' past water inventory. By directly measuring the dehydration behavior of these minerals in their natural environment, we can refine our understanding of water “locked” within ancient aqueously altered martian rocks exposed at the surface and improve the accuracy of water budget estimates. Experiments like this will help bridge the gap between laboratory studies and real martian conditions, providing more reliable data for interpreting Mars' water history.

## 6. Conclusion

A suite of techniques on the Mars 2020 *Perseverance* rover was used to measure the hydration state of minerals freshly exposed within an abrasion patch, at the Fern Glen Rapids member of the Bright Angel formation. During the time-series analysis of the SuperCam dehydration experiment, IRS revealed little to no change in the 1.93 µm H₂O absorption band depth, consistent with prior Mars chamber studies that suggest Ca-sulfates dehydrate slowly under martian surface conditions. Three primary hypotheses may explain the observed hydration stability: (a) adsorbed water escaped before the first measurement took place, which began 22 min post-abrasion, (b) observed hydration signal primarily reflects structural water, with minerals lacking loosely bound components, (c) colder surface temperatures likely de-accelerated or inhibited the process of dehydration, and (d) the Fern Glen Rapids member may have already undergone partial dehydration prior to abrasion.

The SuperCam instrument measured bulk hydration, whereas the SHERLOC instrument classified the hydration phase of individual minerals. SHERLOC indicated the presence of bassanite mixed with anhydrite, corroborating the fact that the Fern Glen Rapids member in Bright Angel is already in a lower hydration state and had possibly undergone dehydration prior to the experiment. Moreover, ferrihydrite is also present but is likely in a moderate hydration state due to the overall shallower water band intensities seen in the SuperCam data. Additionally, the overall hydration state of the Bright Angel formation, including the Fern Glen Rapids member, exhibits lower hydration compared to other units in Jezero crater. Thus, investigating the stability of pristine hydrated phases below the rocks' natural surfaces is integral to understanding the preservation of rocks and mineral stability for planned Mars Sample Return and for accurately assessing the global martian water budget.

Ideally, future iterations of this experiment should prioritize abrasion patches with a higher initial hydration state consisting of minerals known to show significant instability over a short period (e.g., smectites). While SBM represented the first feasible opportunity for such an experiment, subsequent attempts should be optimized with improved knowledge of target mineralogy and hydration potential.
## Conflict of Interest

The authors declare no conflicts of interest relevant to this study.

## Data Availability Statement

This paper's Mars data (including supplemental) are all available in the NASA Planetary Data System (https://pds-geosciences.wustl.edu/missions/mars2020/supercam.htm).

## Acknowledgments

Thank you to the Mars 2020 Science and Engineering teams for supporting the scientific research for this study. CNES supports several contributors for their work with SuperCam on Perseverance (Mars 2020). We would also like to acknowledge the Quick Ternaries Software https://doi.org/10.5281/zenodo.14511222. EAC thanks the Natural Sciences and Engineering Research Council of Canada (Grant RGPIN-2023-03413), the Canadian Space Agency (Grant 22EXPCOI4), and the Canada Foundation for Innovation and Research Manitoba (Grants CFI-1504 and CFI-2450) for supporting this study. SAC, RCW, CB, and TN acknowledge NASA Grant NNH13ZDA018O for supporting this work. SS acknowledges funding from the Swedish National Space Agency (contracts 2021-00092 and 2024-00240). JRJ acknowledges funding from SuperCam subcontract 1532432. LM and CR were supported by a postdoctoral fellowship awarded by the Centre National d'Études Spatiales (CNES). This work was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration 80NM0018D0004. We thank Dr. Debarati Das for her insightful and constructive review of the manuscript.

## References

Alberini, A., Fornaro, T., García-Florentino, C., Biczysko, M., Poblacion, I., Aramendia, J., et al. (2024). Investigating the stability of aromatic carboxylic acids in hydrated magnesium sulfate under UV irradiation to assist detection of organics on Mars. *Scientific Reports*, 14(1), 15945. https://doi.org/10.1038/s41598-024-66669-8

Allwood, A. C., Wade, L. A., Foote, M. C., Elam, W. T., Hurowitz, J. A., Battel, S., et al. (2020). PIXL: Planetary instrument for X-Ray lithochemistry. *Space Science Reviews*, 216(8), 134. https://doi.org/10.1007/s11214-020-00767-7

Anderson, R. B., Forni, O., Cousin, A., Wiens, R. C., Clegg, S. M., Frydenvang, J., et al. (2022). Post-landing major element quantification using SuperCam laser induced breakdown spectroscopy. *Spectrochimica Acta Part B: Atomic Spectroscopy*, 188, 106347. https://doi.org/10.1016/j.sab.2021.106347

Applin, D. M., Izawa, M. R. M., Cloutis, E. A., Goltz, D., & Johnson, J. R. (2015). Oxalate minerals on Mars? *Earth and Planetary Science Letters*, 420, 127-139. https://doi.org/10.1016/j.epsl.2015.03.034

Audouard, J., Poulet, F., Vincendon, M., Milliken, R. E., Jouglet, D., Bibring, J.-P., et al. (2014). Water in the Martian regolith from OMEGA/Mars Express. *Journal of Geophysical Research: Planets*, 119(8), 1969-1989. https://doi.org/10.1002/2014JE004649

Barnes, R., Jones, A., Gupta, S., Horgan, B., Paar, G., Stack, K., et al. (2025). Late deformation of the bright angel formation in western Neretva Vallis, Jezero Crater, Mars. In *56th Lunar and Planetary Science Conference, Abstract #2311*. https://www.hou.usra.edu/meetings/lpsc2025/pdf/2311.pdf

Beck, P., Beyssac, O., Dehouck, E., Bernard, S., Pineau, M., Mandon, L., et al. (2025). From hydrated silica to quartz: Potential hydrothermal precipitates found in Jezero crater, Mars. *Earth and Planetary Science Letters*, 656, 119256. https://doi.org/10.1016/j.epsl.2025.119256

Bedford, C. C., Ravanis, E., Wiens, R. C., Clavé, E., Forni, O., Madariaga, J., et al. (2025). Investigating the origin and alteration history of the Margin Unit in Jezero Crater, Mars with the SuperCam instrument. In *56th Lunar and Planetary Science Conference* (p. 1946). Retrieved from https://www.hou.usra.edu/meetings/lpsc2025/pdf/1946.pdf

Bedford, C. C., Wiens, R. C., Horgan, B. H. N., Klidaras, A., Quantin-Nataf, C., Udry, A., et al. (2025). Geological diversity in the Jezero crater rim investigated with SuperCam: Insights into impact processes on Mars. In *56th Lunar and Planetary Science Conference* (p. 2495). Retrieved from https://www.hou.usra.edu/meetings/lpsc2025/pdf/2495.pdf

Bell, J. F., Maki, J. N., Mehall, G. L., Ravine, M. A., Caplinger, M. A., Bailey, Z. J., et al. (2021). The Mars 2020 perseverance rover mast camera zoom (Mastcam-Z) multispectral, stereoscopic imaging investigation. *Space Science Reviews*, 217(1), 24. https://doi.org/10.1007/s11214-020-00755-x

Beyssac, O., Clavé, E., Udry, A., Dehouck, E., Forni, O., Quantin-Nataf, C., et al. (2024). What are the olivine-rich boulders in the upper fan and margin unit at Jezero Crater, Mars? In *55th Lunar and Planetary Science Conference, Abstract #1493*. Retrieved from https://www.hou.usra.edu/meetings/lpsc2024/pdf/1493.pdf

Bhartia, R., Beegle, L. W., DeFlores, L., Abbey, W., Razzell Hollis, J., Uckert, K., et al. (2021). Perseverance's scanning habitable environments with raman and luminescence for organics and chemicals (SHERLOC) investigation. *Space Science Reviews*, 217(4), 58. https://doi.org/10.1007/s11214-021-00812-z

Bibring, J.-P., Langevin, Y., Gendrin, A., Gondet, B., Poulet, F., Berthé, M., et al. (2005). Mars surface diversity as revealed by the OMEGA/Mars express observations. *Science*, 307(5715), 1576-1581. https://doi.org/10.1126/science.1108806

Bish, D. L., William Carey, J., Vaniman, D. T., & Chipera, S. J. (2003). Stability of hydrous minerals on the martian surface. *Icarus*, 164(1), 96-103. https://doi.org/10.1016/S0019-1035(03)00140-4

Bishop, J. L. (2018). Chapter 3—Remote detection of phyllosilicates on Mars and implications for climate and habitability. In N. A. Cabrol & E. A. Grin (Eds.), *From habitability to life on Mars* (pp. 37–75). Elsevier. https://doi.org/10.1016/B978-0-12-809935-3.00003-7

Bishop, J. L., Lane, M. D., Dyar, M. D., & Brown, A. J. (2008). Reflectance and emission spectroscopy study of four groups of phyllosilicates: Smectites, kaolinite-serpentines, chlorites and micas. *Clay Minerals*, 43(1), 35–54. https://doi.org/10.1180/claymin.2008.043.1.03

Bishop, J. L., & Pieters, C. M. (1995). Low-temperature and low atmospheric pressure infrared reflectance spectroscopy of Mars soil analog materials. *Journal of Geophysical Research*, 100(E3), 5369–5379. https://doi.org/10.1029/94JE03331

Blake, D., Vaniman, D., Achilles, C., Anderson, R., Bish, D., Bristow, T., et al. (2012). Characterization and calibration of the CheMin mineralogical instrument on Mars Science Laboratory. *Space Science Reviews*, 170(1), 341–399. https://doi.org/10.1007/s11214-012-9905-1

Boynton, W., Feldman, W., Mitrofanov, I., Evans, L. G., Reedy, R. C., Squyres, S. W., et al. (2004). The Mars odyssey gamma-ray spectrometer instrument suite. *Space Science Reviews*, 110, 37–83. https://doi.org/10.1023/B:SPAC.0000021007.76126.15

Bristow, T. F., Rampe, E. B., Achilles, C. N., Blake, D. F., Chipera, S. J., Craig, P., et al. (2018). Clay mineral diversity and abundance in sedimentary rocks of Gale crater, Mars. *Science Advances*, 4(6), eaar3330. https://doi.org/10.1126/sciadv.aar3330

Chauviré, B., Pineau, M., Quirico, E., & Beck, P. (2021). Near infrared signature of opaline silica at Mars-relevant pressure and temperature. *Earth and Planetary Science Letters*, 576, 117239. https://doi.org/10.1016/j.epsl.2021.117239

Chipera, S. J., Carey, J. W., & Bish, D. L. (1995). Controlled-humidity XRD analyses: Application to the study of smectite expansion/contraction. *Advances in X-Ray Analysis*, 39, 713-722. https://doi.org/10.1154/S0376030800023168

Chipera, S. J., Vaniman, D. T., Rampe, E. B., Bristow, T. F., Martínez, G., Tu, V. M., et al. (2023). Mineralogical investigation of Mg-Sulfate at the Canaima drill site, gale crater, Mars. *Journal of Geophysical Research: Planets*, 128(11), e2023JE008041. https://doi.org/10.1029/2023JE008041

Clark, R. N., & Roush, T. L. (1984). Reflectance spectroscopy: Quantitative analysis techniques for remote sensing applications. *Journal of Geophysical Research*, 89(B7), 6329–6340. https://doi.org/10.1029/JB089iB07p06329

Clavé, E., Benzerara, K., Meslin, P.-Y., Forni, O., Royer, C., Mandon, L., et al. (2023). Carbonate detection with SuperCam in igneous rocks on the floor of Jezero crater, Mars. *Journal of Geophysical Research: Planets*, 128(6), e2022JE007463. https://doi.org/10.1029/2022JE007463
Cloutis, E. A., Craig, M. A., Kruzelecky, R. V., Jamroz, W. R., Scott, A., Hawthorne, F. C., & Mertzman, S. A. (2008). Spectral reflectance properties of minerals exposed to simulated Mars surface conditions. *Icarus*, *195*(1), 140–168. https://doi.org/10.1016/j.icarus.2007.10.028

Cloutis, E. A., Craig, M. A., Mustard, J. F., Kruzelecky, R. V., Jamroz, W. R., Scott, A., et al. (2007). Stability of hydrated minerals on Mars. *Geophysical Research Letters*, *34*(20). https://doi.org/10.1029/2007GL031267

Connell, S. A., Applin, D. M., Cloutis, E. A., Poitras, J. T., Dixon, D. T., Mertzman, S. A., et al. (2025). Spectral reflectance (0.35–2.50 µm) properties of minerals and organic-bearing compounds exposed to current Martian surface conditions. *Icarus*, *441*, 116712. https://doi.org/10.1016/j.icarus.2025.116712

Connell, S. A., Wiens, R. C., Royer, C., Bedford, C. C., Mandon, L., Siljeström, S., et al. (2025). Abrasion dehydration experiment at Bright Angel, Jezero Crater, using SuperCam onboard perseverance. In *56th Lunar and Planetary Science Conference, Abstract #282*. Retrieved from https://www.hou.usra.edu/meetings/lpsc2025/pdf/1282.pdf

Corpolongo, A., Jakubek, R. S., Burton, A. S., Brown, A. J., Yanchilina, A., Czaja, A. D., et al. (2023). SHERLOC raman mineral class detections of the Mars 2020 crater floor campaign. *Journal of Geophysical Research: Planets*, *128*(3), e2022JE007455. https://doi.org/10.1029/2022JE007455

Dehouck, E., Forni, O., Quantin-Nataf, C., Beck, P., Mangold, N., Royer, C., et al. (2023). Overview of the bedrock geochemistry and mineralogy observed by SuperCam during Perseverance's Delta Front Campaign. In *54th Lunar and Planetary Science Conference* (Vol. 54, p. 2862). Retrieved from https://hal.science/hal-04045001

Dehouck, E., McLennan, S. M., Sklute, E. C., & Dyar, M. D. (2017). Stability and fate of ferrihydrite during episodes of water/rock interactions on early Mars: An experimental approach. *Journal of Geophysical Research: Planets*, *122*(2), 358–382. https://doi.org/10.1002/2016JE005222

Ehlmann, B. L., Mustard, J. F., Murchie, S. L., Bibring, J.-P., Meunier, A., Fraeman, A. A., & Langevin, Y. (2011). Subsurface water and clay mineral formation during the early history of Mars. *Nature*, *479*(7371), 53–60. Article 7371. https://doi.org/10.1038/nature10582

Farley, K. A., Stack, K. M., Shuster, D. L., Horgan, B. H. N., Hurowitz, J. A., Tarnas, J. D., et al. (2022). Aqueously altered igneous rocks sampled on the floor of Jezero crater, Mars. *Science*, *377*(6614), eab02196. https://doi.org/10.1126/science.ab02196

Farley, K. A., Williford, K. H., Stack, K. M., Bhartia, R., Chen, A., de la Torre, M., et al. (2020). Mars 2020 mission overview. *Space Science Reviews*, *216*(8), 142. https://doi.org/10.1007/s11214-020-00762-y

Fassett, C. I., & Head, J. W. III. (2005). Fluvial sedimentary deposits on Mars: Ancient deltas in a crater lake in the Nili Fossae region. *Geophysical Research Letters*, *32*(14). https://doi.org/10.1029/2005GL023456

Fischer, E., Martínez, G. M., Rennó, N. O., Tamppari, L. K., & Zent, A. P. (2019). Relative humidity on Mars: New results from the Phoenix TECP sensor. *Journal of Geophysical Research: Planets*, *124*(11), 2780–2792. https://doi.org/10.1029/2019JE006080

Fornaro, T., Brucato, J. R., Poggiali, G., Corazzi, M. A., Biczysko, M., Jaber, M., et al. (2020). UV irradiation and near infrared characterization of laboratory Mars soil analog samples. *Frontiers in Astronomy and Space Sciences*, *7*. https://doi.org/10.3389/fspas.2020.539289

Fouchet, T., Reess, J.-M., Montmessin, F., Hassen-Khodja, R., Nguyen-Tuong, N., Humeau, O., et al. (2022). The SuperCam infrared spectrometer for the perseverance rover of the Mars2020 mission. *Icarus*, *373*, 114773. https://doi.org/10.1016/j.icarus.2021.114773

Fraeman, A. A., Ehlmann, B. L., Arvidson, R. E., Edwards, C. S., Grotzinger, J. P., Milliken, R. E., et al. (2016). The stratigraphy and evolution of lower Mount Sharp from spectral, morphological, and thermophysical orbital data sets. *Journal of Geophysical Research: Planets*, *121*(9), 1713–1736. https://doi.org/10.1002/2016JE005095

Gaffey, S. J. (1987). Spectral reflectance of carbonate minerals in the visible and near infrared (0.35–2.55 um): Anhydrous carbonate minerals. *Journal of Geophysical Research*, *92*(B2), 1429–1440. https://doi.org/10.1029/JB092iB02p01429

Garefalakis, P., do Prado, A. H., Mair, D., Douillet, G. A., Nyffenegger, F., & Schlunegger, F. (2023). Comparison of three grain size measuring methods applied to coarse-grained gravel deposits. *Sedimentary Geology*, *446*, 106340. https://doi.org/10.1016/j.sedgeo.2023.106340

Gómez-Elvira, J., Armiens, C., Castañer, L., Domínguez, M., Genzer, M., Gómez, F., et al. (2012). REMS: The environmental sensor suite for the Mars science laboratory rover. *Space Science Reviews*, *170*(1), 583–640. https://doi.org/10.1007/s11214-012-9921-1

Goudge, T. A., Milliken, R. E., Head, J. W., Mustard, J. F., & Fassett, C. I. (2017). Sedimentological evidence for a deltaic origin of the western fan deposit in Jezero crater, Mars and implications for future exploration. *Earth and Planetary Science Letters*, *458*, 357–365. https://doi.org/10.1016/j.epsl.2016.10.056

Goudge, T. A., Mustard, J. F., Head, J. W., Fassett, C. I., & Wiseman, S. M. (2015). Assessing the mineralogy of the watershed and fan deposits of the Jezero crater paleolake system, Mars. *Journal of Geophysical Research: Planets*, *120*(4), 775–808. https://doi.org/10.1002/2014JE004782

Grotzinger, J. P., Crisp, J., Vasavada, A. R., Anderson, R. C., Baker, C. J., Barry, R., et al. (2012). Mars science laboratory mission and science investigation. *Space Science Reviews*, *170*(1), 5–56. https://doi.org/10.1007/s11214-012-9892-2

Hansen, P. B. (2022). *Modeling of LIBS Spectra Obtained in Martian Atmospheric Conditions*. Mathematisch-Naturwissenschaftliche Facultät. https://doi.org/10.18452/25303

Harner, P. L., & Gilmore, M. S. (2015). Visible-near infrared spectra of hydrous carbonates, with implications for the detection of carbonates in hyperspectral data of Mars. *Icarus*, *250*, 204–214. https://doi.org/10.1016/j.icarus.2014.11.037

Hausrath, E. M., Adcock, C. T., Bechtold, A., Beck, P., Benison, K., Brown, A., et al. (2023). An examination of soil crusts on the floor of Jezero crater, Mars. *Journal of Geophysical Research: Planets*, *128*(10), e2022JE007433. https://doi.org/10.1029/2022JE007433

Horgan, B. H. N., Anderson, R. B., Dromart, G., Amador, E. S., & Rice, M. S. (2020). The mineral diversity of Jezero crater: Evidence for possible lacustrine carbonates on Mars. *Icarus*, *339*, 113526. https://doi.org/10.1016/j.icarus.2019.113526

Hurowitz, J. A., McLennan, S. M., Tosca, N. J., Arvidson, R. E., Michalski, J. R., Ming, D. W., et al. (2006). In situ and experimental evidence for acidic weathering of rocks and soils on Mars. *Journal of Geophysical Research*, *111*(E2). https://doi.org/10.1029/2005JE002515

Hurowitz, J. A., Tice, M. M., Allwood, A. C., Cable, M. L., Hand, K. P., Murphy, A. E., et al. (2025). Redox-driven mineral and organic associations in Jezero Crater, Mars. *Nature*, *645*(8080), 332–340. https://doi.org/10.1038/s41586-025-09413-0

Jones, A. J., Barnes, R., Gupta, S., Paar, G., Horgan, B., Garczynski, B., et al. (2025). Is the Bright Angel Formation (Neretva Vallis, Jezero Crater, Mars) a valley-confined lacustrine succession? In *56th Lunar and Planetary Science Conference, Abstract #1984*. Retrieved from https://www.hou.usra.edu/meetings/lpsc2025/pdf/1984.pdf

Lemmon, M. T., Smith, M. D., Viudez-Moreiras, D., de la Torre-Juarez, M., Vicente-Retortillo, A., Munguira, A., et al. (2022). Dust, sand, and winds within an active martian storm in Jezero crater. *Geophysical Research Letters*, *49*(17), e2022GL100126. https://doi.org/10.1029/2022GL100126

Mahaffy, P. R., Webster, C. R., Atreya, S. K., Franz, H., Wong, M., Conrad, P. G., et al. (2013). Abundance and isotopic composition of gases in the Martian atmosphere from the curiosity rover. *Science*, *341*(6143), 263–266. https://doi.org/10.1126/science.1237966

Mahaffy, P. R., Webster, C. R., Cabane, M., Conrad, P. G., Coll, P., Atreya, S. K., et al. (2012). The sample analysis at Mars investigation and instrument suite. *Space Science Reviews*, *170*(1), 401–478. https://doi.org/10.1007/s11214-012-9879-z

Mandon, L., Beck, P., Quantin-Nataf, C., Dehouck, E., Thollot, P., Loizeau, D., & Volat, M. (2022). ROMA: A database of rock reflectance spectra for martian in situ exploration. *Earth and Space Science*, *9*(1), e2021EA001871. https://doi.org/10.1029/2021EA001871
Mandon, L., Ehlmann, B. L., Wiens, R. C., Garczynski, B. J., Horgan, B. H. N., Fouchet, T., et al. (2024). Variable iron mineralogy and redox conditions recorded in ancient rocks measured by in situ visible/near-infrared spectroscopy at Jezero crater, Mars. *Journal of Geophysical Research: Planets*, 129, e2023JE008254. https://doi.org/10.1029/2023JE008254

Mandon, L., Ehlmann, B. L., Wiens, R. C., Horgan, B., Garczynski, B. J., Johnson, J. R., et al. (2023). Variable past-redox conditions at jezero crater, Mars. 2806, 1423. In *54th Lunar and Planetary Science Conference*.

Mandon, L., Forni, O., Mangold, N., Wiens, R. C., Manelski, H. T., Wolf, Z. U., et al. (2025). Diagenetically altered fine sediments at Neretva Vallis, Mars. In *56th Lunar and Planetary Science Conference, Abstract #1400*. Retrieved from https://www.hou.usra.edu/meetings/lpsc2025/pdf

Mandon, L., Quantin-Nataf, C., Royer, C., Beck, P., Fouchet, T., Johnson, J. R., et al. (2023). Reflectance of Jezero crater floor: 2. Mineralogical interpretation. *Journal of Geophysical Research: Planets*, 128(7), e2022JE007450. https://doi.org/10.1029/2022JE007450

Mandon, L., Quantin-Nataf, C., Thollot, P., Mangold, N., Lozac'h, L., Dromart, G., et al. (2020). Refining the age, emplacement and alteration scenarios of the olivine-rich unit in the Nili Fossae region, Mars. *Icarus*, 336, 113436. https://doi.org/10.1016/j.icarus.2019.113436

Mangold, N., Gupta, S., Gasnault, O., Dromart, G., Tarnas, J. D., Sholes, S. F., et al. (2021). Perseverance rover reveals an ancient Delta-Lake system and flood deposits at Jezero crater, Mars. *Science*, 374(6568), 711–717. https://doi.org/10.1126/science.abl4051

Manrique, J. A., Clavé, E., Lopez-Reyes, G., Beyssac, O., Ollila, A. M., Forni, O., et al. (2025). SuperCam's Raman observations during the Margin Unit and Crater Rim campaigns. In *56th Lunar and Planetary Science Conference, Abstract #2333*. Retrieved from https://www.hou.usra.edu/meetings/lpsc2025/pdf

Martínez, G. M., Newman, C. N., De Vicente-Retortillo, A., Fischer, E., Renno, N. O., Richardson, M. I., et al. (2017). The modern near-surface Martian climate: A review of in-situ meteorological data from Viking to curiosity. *Space Science Reviews*, 212(1), 295–338. https://doi.org/10.1007/s11214-017-0360-x

Martínez, G. M., Sebastián, E., Vicente-Retortillo, A., Smith, M. D., Johnson, J. R., Fischer, E., et al. (2023). Surface energy budget, Albedo, and thermal inertia at Jezero crater, Mars, as observed from the Mars 2020 MEDA instrument. *Journal of Geophysical Research: Planets*, 128(2), e2022JE007537. https://doi.org/10.1029/2022JE007537

Maurice, S., Wiens, R. C., Bernardi, P., Caïs, P., Robinson, S., Nelson, T., et al. (2021). The SuperCam instrument suite on the Mars 2020 rover: Science objectives and mast-unit description. *Space Science Reviews*, 217(3), 47. https://doi.org/10.1007/s11214-021-00807-w

Milliken, R. E., & Mustard, J. F. (2005). Quantifying absolute water content of minerals using near-infrared reflectance spectroscopy. *Journal of Geophysical Research*, 110(E12). https://doi.org/10.1029/2005JE002534

Milliken, R. E., Mustard, J. F., Poulet, F., Jouglet, D., Bibring, J.-P., Gondet, B., & Langevin, Y. (2007). Hydration state of the Martian surface as seen by Mars Express OMEGA: 2. H2O content of the surface. *Journal of Geophysical Research*, 112(E8). https://doi.org/10.1029/2006JE002853

Moeller, R. C., Jandura, L., Rosette, K., Robinson, M., Samuels, J., Silverman, M., et al. (2020). The Sampling and Caching Subsystem (SCS) for the scientific exploration of Jezero crater by the Mars 2020 perseverance rover. *Space Science Reviews*, 217(1), 5–1504. https://doi.org/10.1007/s11214-020-00783-7

Montmessin, F., Fedorova, A., Alday, J., Aoki, S., Chaffin, M., Chaufray, J.-Y., et al. (2024). Mars' water cycle and escape: A view from Mars express and beyond. *Space Science Reviews*, 220(7), 77. https://doi.org/10.1007/s11214-024-01099-6

Morris, R. V., Ming, D. W., Golden, D. C., Graff, T. G., & Achilles, C. N. (2010). Evidence for interlayer collapse of nontronite on Mars from laboratory visible and Near-IR reflective spectra. Retrieved from https://ntrs.nasa.gov/citations/20100005628

Mukhin, L. M., Koscheevi, A. P., Dikov, Y. P., Huth, J., & Wänke, H. (1996). Experimental simulations of the photodecomposition of carbonates and sulphates on Mars. *Nature*, 379(6561), 141–143. https://doi.org/10.1038/379141a0

Munguira, A., Hueso, R., Sánchez-Lavega, A., de la Torre-Juarez, M., Martínez, G. M., Newman, C. E., et al. (2023). Near surface atmospheric temperatures at Jezero from Mars 2020 MEDA measurements. *Journal of Geophysical Research: Planets*, 128(3), e2022JE007559. https://doi.org/10.1029/2022JE007559

Murchie, S., Arvidson, R., Bedini, P., Beisser, K., Bibring, J.-P., Bishop, J., et al. (2007). Compact reconnaissance imaging spectrometer for Mars (CRISM) on Mars Reconnaissance Orbiter (MRO). *Journal of Geophysical Research*, 112(E5). https://doi.org/10.1029/2006JE002682

Murphy, A. E., Uckert, K., Hand, K. P., Bhartia, R., Bykov, S. V., Hickman-Lewis, K., et al. (2025). Spatially resolved complex organic matter detected in an ancient river valley in Jezero crater, Mars. In *56th Lunar and Planetary Science Conference, Abstract #2241*. Retrieved from https://www.hou.usra.edu/meetings/lpsc2025/pdf

Mustard, J. F. (2019). Chapter 8 - Sequestration of volatiles in the Martian crust through hydrated minerals: A significant planetary reservoir of water. In J. Filiberto & S. P. Schwenzer (Eds.), *Volatiles in the Martian crust* (pp. 247–263). Elsevier. https://doi.org/10.1016/B978-0-12-804191-8.00008-8

Nayama, V. S., Lala, M. G. N., & Krishna, A. P. (2023). Seasonal variation of Martian surface temperature over gale crater and surroundings. *Solar System Research*, 57(1), 14–24. https://doi.org/10.1134/S0038094623010045

Patel, M. R., Bérces, A., Kerékgyárto, T., Rontó, G., Lammer, H., & Zarnnecki, J. C. (2004). Annual solar UV exposure and biological effective dose rates on the Martian surface. *Advances in Space Research*, 33(8), 1247–1252. https://doi.org/10.1016/j.asr.2003.08.036

Phua, Y. Y., Ehlmann, B. L., Siljeström, S., Czaja, A. D., Beck, P., Connell, S., et al. (2024). Characterizing hydrated sulfates and altered phases in Jezero crater fan and floor geologic units with SHERLOC on Mars 2020. *Journal of Geophysical Research: Planets*, 129(7), e2023JE008251. https://doi.org/10.1029/2023JE008251

Poitras, J. T., Cloutis, E. A., Salvatore, M. R., Mertzman, S. A., Applin, D. M., & Mann, P. (2018). Mars analog minerals' spectral reflectance characteristics under Martian surface conditions. *Icarus*, 306, 50–73. https://doi.org/10.1016/j.icarus.2018.01.023

Polkko, J., Hieta, M., Harri, A.-M., Tamppari, L., Martínez, G., Viúdez-Moreiras, D., et al. (2023). Initial results of the relative humidity observations by MEDA instrument onboard the Mars 2020 perseverance rover. *Journal of Geophysical Research: Planets*, 128(2), e2022JE007447. https://doi.org/10.1029/2022JE007447

Poulet, F., Royer, C., Forni, O., Dehouck, E., Quantin-Nataf, C., Johnson, J. R., et al. (2024). Investigating the modal mineralogy of olivine- and LCP-rich boulders identified in Jezero Crater. In *Tenth International Conference on Mars, Abstract #3107*. Retrieved from https://www.hou.usra.edu/meetings/tenthmars2024/pdf/3107.pdf

Quantin-Nataf, C., Mandon, L., Dehouck, E., Forni, O., Beck, P., Poulet, F., et al. (2024). Orbital infrared spectroscopy: Lessons learned from in situ SCAM VISIR spectrometer in jezero. In *Tenth International Conference on Mars, Pasadena*. Retrieved from https://www.hou.usra.edu/meetings/tenthmars2024/pdf/3390.pdf

Rapin, W., Bousquet, B., Lasue, J., Meslin, P.-Y., Lacour, J.-L., Fabre, C., et al. (2017). Roughness effects on the hydrogen signal in laser-induced breakdown spectroscopy. *Spectrochimica Acta Part B: Atomic Spectroscopy*, 137, 13–22. https://doi.org/10.1016/j.sab.2017.09.003

Razzell Hollis, J., Moore, K. R., Sharma, S., Beegle, L., Grotzinger, J. P., Allwood, A., et al. (2022). The power of paired proximity science observations: Co-located data from SHERLOC and PIXL on Mars. *Icarus*, 387, 115179. https://doi.org/10.1016/j.icarus.2022.115179
Riu, L., Carter, J., Poulet, F., Cardesín-Moinelo, A., & Martin, P. (2023). Global surficial water content stored in hydrated silicates at Mars from OMEGA/Mex. *Icarus*, **398**, 115537. https://doi.org/10.1016/j.icarus.2023.115537

Rivera-Valentín, E., Martínez, G., Filiberto, J., Lynch, K., Chevrier, V. F., Gough, R. V., et al. (2021). Resolving the water cycle on a salty Mars: Planetary science and astrobiology exploration strategies for the next decade. *Bulletin of the AAS*, **53**(4). Article 4. https://doi.org/10.3847/25c2cfeb.b0e3963b

Rodríguez-Manfredi, J. A., de la Torre Juárez, M., Alonso, A., Apéstigue, V., Arruego, I., Atienza, T., et al. (2021). The Mars Environmental Dynamics Analyzer, MEDA. A suite of environmental Sensors for the Mars 2020 Mission. *Space Science Reviews*, **217**(3), 48. https://doi.org/10.1007/s11214-021-00816-9

Royer, C., Bedford, C. C., Johnson, J. R., Horgan, B., Broz, A., Forni, O., et al. (2024). Intense alteration on early Mars revealed by high-aluminum rocks at Jezero Crater. *Nature Earth and Environment*, **5**(1), 671. https://doi.org/10.1038/s43247-024-01837-2

Royer, C., Bernard, S., Beyssac, O., Balan, E., Forni, O., Gauthier, M., et al. (2024). Impact of UV radiation on the Raman and infrared spectral signatures of sulfates, phosphates and carbonates: Implications for Mars exploration. *Icarus*, **410**, 115894. https://doi.org/10.1016/j.icarus.2023.115894

Savijärvi, H., Polkko, J., Hieta, M., Martinez, G., Zorzano, M.-P., Tamppari, L., & Harri, A.-M. (2024). Moisture cycles in Jezero crater, Mars. *Icarus*, **423**, 116283. https://doi.org/10.1016/j.icarus.2024.116283

Savijärvi, H. I., Martinez, G. M., Fischer, E., Renno, N. O., Tamppari, L. K., Kent, A., & Harri, A.-M. (2020). Humidity observations and column simulations for a warm period at the Mars Phoenix lander site: Constraining the adsorptive properties of regolith. *Icarus*, **343**, 113688. https://doi.org/10.1016/j.icarus.2020.113688

Scheller, E. L., Ehlmann, B. L., Hu, R., Adams, D. J., & Yung, Y. L. (2021). Long-term drying of Mars by sequestration of ocean-scale volumes of water in the crust. *Science*, **372**(6537), 56–62. https://doi.org/10.1126/science.abc7717

Scheller, E. L., Razzell Hollis, J., Cardarelli, E. L., Steele, A., Beegle, L. W., Bhartia, R., et al. (2022). Aqueous alteration processes in Jezero crater, Mars—Implications for organic geochemistry. *Science*, **378**(6624), 1105–1110. https://doi.org/10.1126/science.abo5204

Schon, S. C., Head, J. W., & Fassett, C. I. (2012). An overfilled lacustrine system and progradational delta in Jezero crater, Mars: Implications for Noachian climate. *Planetary and Space Science*, **67**(1), 28–45. https://doi.org/10.1016/j.pss.2012.02.003

Schröder, S., Meslin, P.-Y., Gasnault, O., Maurice, S., Cousin, A., Wiens, R. C., et al. (2015). Hydrogen detection with ChemCam at Gale crater. *Icarus*, **249**, 43–61. https://doi.org/10.1016/j.icarus.2014.08.029

Schröder, S., Rammelkamp, K., Hansen, P. B., Seel, F., Cousin, A., Forni, O., et al. (2023). Semiquantitative analysis of ChemCam and SuperCam LIBS data with spectral (Vol. 2806).

Sharma, S., Roppel, R. D., Murphy, A. E., Beegle, L. W., Bhartia, R., Steele, A., et al. (2023). Diverse organic-mineral associations in Jezero crater, Mars. *Nature*, **619**(7971), 724–732. https://doi.org/10.1038/s41586-023-06143-z

Siebach, K., Nachon, M., Sholes, S., Sun, V. Z., Sesto, T. D., Weiss, B. P., et al. (2023). Overview of perseverance's upper fan campaign. AGU23. Retrieved from https://agu.confex.com/agu/fm23/meetingapp.cgi/Paper/1325383

Siljeström, S., Czaja, A. D., Corpolongo, A., Berger, E. L., Li, A. Y., Cardarelli, E., et al. (2024). Evidence of sulfate-rich fluid alteration in jezero Crater floor, Mars. *Journal of Geophysical Research: Planets*, **129**(1), e2023JE007989. https://doi.org/10.1029/2023JE007989

Spanovich, N., Smith, M. D., Smith, P. H., Wolff, M. J., Christensen, P. R., & Squyres, S. W. (2006). Surface and near-surface atmospheric temperatures for the Mars Exploration Rover landing sites. *Icarus*, **180**(2), 314–320. https://doi.org/10.1016/j.icarus.2005.09.014

Srivastava, A., Steele, A., Kah, L. C., Conrad, P. G., Sharma, S., Phua, Y. Y., et al. (2025). In-situ observation of hydrated carbonate in Jezero Crater, Mars. *Lunar and Planetary Science*, **56**, 1595. Retrieved from https://www.hou.usra.edu/meetings/lpsc2025/pdf/1595.pdf

Stack, K. M., Ives, L. R. W., Gupta, S., Lamb, M. P., Tebolt, M., Caravaca, G., et al. (2024). Sedimentology and stratigraphy of the Shenandoah Formation, Western Fan, Jezero Crater, Mars. *Journal of Geophysical Research: Planets*, **129**(2), e2023JE008187. https://doi.org/10.1029/2023JE008187

Stawski, T. M., Besselink, R., Chatzipanagis, K., Hövelmann, J., Benning, L. G., & Van Driessche, A. E. S. (2020). Nucleation pathway of calcium sulfate hemihydrate (Bassanite) from solution: Implications for calcium sulfates on Mars. *Journal of Physical Chemistry C*, **124**(15), 8411–8422. https://doi.org/10.1021/acs.jpcc.0c01041

Sun, V. Z., Hand, K. P., Stack, K. M., Farley, K. A., Simon, J. I., Newman, C., et al. (2023). Overview and results from the Mars 2020 perseverance Rover's first science campaign on the Jezero Crater floor. *Journal of Geophysical Research: Planets*, **128**(6), e2022JE007613. https://doi.org/10.1029/2022JE007613

Tice, M. M., Hurowitz, J. A., Allwood, A. C., Jones, M. W. M., Orenstein, B. J., Davidoff, S., et al. (2022). Alteration history of Sétah formation rocks inferred by PIXL X-ray fluorescence, X-ray diffraction, and multispectral imaging on Mars. *Science Advances*, **8**(47), eabp9084. https://doi.org/10.1126/sciadv.abp9084

Treiman, A. H., Morris, R. V., Agresti, D. G., Graff, T. G., Achilles, C. N., Rampe, E. B., et al. (2014). Ferrian saponite from the Santa Monica Mountains (California, U.S.A., Earth): Characterization as an analog for clay minerals on Mars with application to Yellowknife Bay in Gale Crater. *American Mineralogist*, **99**(11–12), 2234–2250. https://doi.org/10.2138/am-2014-4763

Turenne, N., Parkinson, A., Applin, D. M., Mann, P., Cloutis, E. A., & Mertzman, S. A. (2022). Spectral reflectance properties of minerals exposed to martian surface conditions: Implications for spectroscopy-based mineral detection on Mars. *Planetary and Space Science*, **210**, 105377. https://doi.org/10.1016/j.pss.2021.105377

Uckert, K. (2022). *Loupe* (version V5.1.5). Zenodo. https://doi.org/10.5281/zenodo.7062998

Udry, A., Beyssac, O., Forni, O., Clave, E., Bedford, C., Beck, P., et al. (2025). Igneous compositions in the rim of Jezero crater using SuperCam data. *Lunar and Planetary Science*, **56**, 1352. Retrieved from https://www.hou.usra.edu/meetings/lpsc2025/pdf/1352.pdf

Valantinas, A., Mustard, J. F., Chevrier, V., Mangold, N., Bishop, J. L., Pommerol, A., et al. (2025). Detection of ferrihydrite in Martian red dust records ancient cold and wet conditions on Mars. *Nature Communications*, **16**(1), 1712. https://doi.org/10.1038/s41467-025-56970-z

Vaniman, D., Chipera, S., Rampe, E., Bristow, T., Blake, D., Meusburger, J., et al. (2024). Gypsum on Mars: A detailed view at Gale crater. *Minerals*, **14**(8). Article 8. https://doi.org/10.3390/min14080815

Vaniman, D. T., Bish, D. L., Chipera, S. J., Fialips, C. I., William Carey, J., & Feldman, W. C. (2004). Magnesium sulphate salts and the history of water on Mars. *Nature*, **431**(7009), 663–665. https://doi.org/10.1038/nature02973

Vaniman, D. T., Martínez, G. M., Rampe, E. B., Bristow, T. F., Blake, D. F., Yen, A. S., et al. (2018). Gypsum, bassanite, and anhydrite at Gale crater, Mars. *American Mineralogist*, **103**(7), 1011–1020. https://doi.org/10.2138/am-2018-6346

Vaughan, A. F., Rice, M., Klidaras, A., Johnson, J. R., Gwizd, S., Horgan, B., et al. (2025). The boulder-rich blocky unit of the Western jezero upper fan: Discriminating olivine and pyroxene compositions and constraining provenance. *Journal of Geophysical Research: Planets*, **130**(10). https://doi.org/10.1029/2025JE009159
Vicente-Retortillo, A., Lemmon, M. T., Martínez, G. M., Toledo, D., Apéstigue, V., Arruego, I., et al. (2024). Dust accumulation and lifting at the landing site of the Mars 2020 mission, Jezero crater, as observed from MEDA. *Geophysical Research Letters*, 51(11), e2023GL107975. https://doi.org/10.1029/2023GL107975

Vicente-Retortillo, Á., Valero, F., Vázquez, L., & Martínez, G. M. (2015). A model to calculate solar radiation fluxes on the Martian surface. *Journal of Space Weather and Space Climate*, 5, A33. https://doi.org/10.1051/swsc/2015035

Viviano, C. E., Seelos, F. P., Murchie, S. L., Kahn, E. G., Seelos, K. D., Taylor, H. W., et al. (2014). Revised CRISM spectral parameters and summary products based on the currently detected mineral diversity on Mars. *Journal of Geophysical Research: Planets*, 119(6), 1403–1431. https://doi.org/10.1002/2014JE004627

Wang, A., Freeman, J. J., & Jolliff, B. L. (2009). Phase transition pathways of the hydrates of magnesium sulfate in the temperature range 50°C to 5°C: Implication for sulfates on Mars. *Journal of Geophysical Research*, 114(E4). https://doi.org/10.1029/2008JE003266

Werner, S. C. (2008). The early martian evolution—Constraints from basin formation ages. *Icarus*, 195(1), 45–60. https://doi.org/10.1016/j.icarus.2007.12.008

Wiens, R. C., Maurice, S., Robinson, S. H., Nelson, A. E., Cais, P., Bernardi, P., et al. (2020). The SuperCam instrument suite on the NASA Mars 2020 rover: Body unit and combined system tests. *Space Science Reviews*, 217(1), 4. https://doi.org/10.1007/s11214-020-00777-5

Wiens, R. C., Udry, A., Beyssac, O., Quantin-Nataf, C., Mangold, N., Cousin, A., et al. (2022). Compositionally and density stratified igneous terrain in Jezero crater, Mars. *Science Advances*, 8(34), eab03399. https://doi.org/10.1126/sciadv.ab03399

Zorzano, M.-P., Martínez, G., Polkko, J., Tamppari, L. K., Newman, C., Savijärvi, H., et al. (2024). Present-day thermal and water activity environment of the Mars Sample Return collection. *Scientific Reports*, 14(1), 7175. https://doi.org/10.1038/s41598-024-57458-4

## References From the Supporting Information

David, G., Dehouck, E., Meslin, P.-Y., Rapin, W., Cousin, A., Forni, O., et al. (2022). Evidence for amorphous sulfates as the main carrier of soil hydration in gale crater, Mars. *Geophysical Research Letters*, 49(21), e2022GL098755. https://doi.org/10.1029/2022GL098755

Jones, M. W. M., Flannery, D. T., Hurowitz, J. A., Tice, M. T., Schrank, C. E., Allwood, A. C., et al. (2024). In-situ crystallographic mapping constrains sulfate deposition and timing in Jezero crater. *MARS*. arXiv. https://doi.org/10.48550/arXiv.2410.05615

Karunatillake, S., Wray, J. J., Gasnault, O., McLennan, S. M., Rogers, A. D., Squyres, S. W., et al. (2014). Sulfates hydrating bulk soil in the Martian low and middle latitudes. *Geophysical Research Letters*, 41(22), 7987–7996. https://doi.org/10.1002/2014GL061136

Kokaly, R. F., Clark, R. N., Swayze, G. A., Livo, K. E., Hoefen, T. M., Pearson, N. C., et al. (2017). USGS Spectral Library version 7: U.S. Geological Survey Data Series, 1035, 61. https://doi.org/10.3133/ds1035

Nachon, M., Clegg, S. M., Mangold, N., Schröder, S., Kah, L. C., Dromart, G., et al. (2014). Calcium sulfate veins characterized by ChemCam/ Curiosity at Gale crater, Mars. *Journal of Geophysical Research: Planets*, 119(9), 1991–2016. https://doi.org/10.1002/2013JE004588

Rampe, E. B., Bristow, T. F., Morris, R. V., Morrison, S. M., Achilles, C. N., Ming, D. W., et al. (2020). Mineralogy of vera Rubin Ridge from the Mars science laboratory CheMin instrument. *Journal of Geophysical Research: Planets*, 125(9), e2019JE006306. https://doi.org/10.1029/2019JE006306

Rapin, W., Meslin, P.-Y., Maurice, S., Vaniman, D., Nachon, M., Mangold, N., et al. (2016). Hydration state of calcium sulfates in Gale crater, Mars: Identification of bassanite veins. *Earth and Planetary Science Letters*, 452, 197–205. https://doi.org/10.1016/j.epsl.2016.07.045

Wilson, S., & Bish, D. L. (2012). Stability of Mg-sulfate minerals in the presence of smectites: Possible mineralogical controls on H2O cycling and biomarker preservation on Mars. *Geochimica et Cosmochimica Acta*, 96, 120–133. https://doi.org/10.1016/j.gca.2012.08.008