Journal of Geophysical Research: Planets最新文献

{"title":"A Statistical Study of the Vertical Scale Height of the Martian Ionosphere Using MAVEN Observations","authors":"Wendong Liu,&nbsp;Libo Liu,&nbsp;Yiding Chen,&nbsp;Huijun Le,&nbsp;Yuyan Yang,&nbsp;Wenbo Li,&nbsp;Han Ma,&nbsp;Hui Zhang","doi":"10.1029/2024JE008450","DOIUrl":"https://doi.org/10.1029/2024JE008450","url":null,"abstract":"<p>The Vertical Scale Height (VSH) is a crucial parameter that describes the shape of the ionospheric electron density profile. Evidence suggests a complex relationship between VSH and the thermal structure and dynamics of the ionosphere. A statistical study was conducted on the VSH at low altitudes (175 km) and high altitudes (300 km) in the Martian ionosphere, using data from the MAVEN observations from 2014 to 2023. The results suggest that the influence of the crustal magnetic field on VSH₁₇₅ is more pronounced than on VSH₃₀₀. VSH₁₇₅ shows a minor peak around −20° latitudes, which is more than 7% higher than the average value, and an increasing trend with latitude in the northern hemisphere. VSH₃₀₀ is higher in the southern hemisphere than in the northern hemisphere, especially in summer, by approximately 42.1%. Regarding the local time variation of VSH, we observed an increasing trend from midnight to morning and a decreasing trend from dusk to midnight in almost all conditions. The local time variation of VSH also exhibits seasonal and latitudinal dependence. These variations have different levels of consistency with the gradient of the electron temperature (Te) and the collision frequency between charged particles and neutrals. Specifically, the correlation coefficient between VSH₁₇₅ and the collision frequency between charged particles and neutrals reaches as high as 0.93 in the northern hemisphere winter and southern hemisphere summer. The correlation coefficient between VSH₃₀₀ and the gradient of the Te reaches up to 0.72 in the southern hemisphere equinox.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"129 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142041566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Large Glacier-Like Forms on Mars: Insights From Crater Morphologies and Crater Retention Ages","authors":"G. Driver,&nbsp;M. R. El-Maarry,&nbsp;B. Hubbard,&nbsp;S. Brough","doi":"10.1029/2023JE008207","DOIUrl":"https://doi.org/10.1029/2023JE008207","url":null,"abstract":"<p>Glacier-Like Forms (GLFs) are a subset of ice-rich landforms known as Viscous Flow Features that populate Mars' mid-latitudes. GLFs are morphologically similar to terrestrial valley glaciers and are thought to result from the redistribution of water ice from the Martian poles during periods of high obliquity throughout the Amazonian period. Their ages, formation, and evolutionary processes are poorly constrained. We selected the 100 largest GLFs from the most recent GLF population data set, and by analyzing their superimposing crater morphologies and populations, we calculated their Crater Retention Ages (CRAs) and identified any relationships between CRAs, crater morphologies, and GLF geometries. We also organized the crater morphologies into states of degradation based on the understood erosional sequences. 3,630 craters were mapped, which we classified into 15 different crater morphologies. We calculated 98 CRAs, ranging from ∼2.88 Ma to ∼3.5 Ga. On average, GLFs in the southern hemisphere have younger CRAs, higher average slopes, smaller crater populations, and show less variability in crater morphological development than in the northern hemisphere. GLFs with higher mean slopes display less crater morphology variety, suggesting that shallow GLFs experience less reworking than steeper GLFs. We propose that these regional and hemispheric differences are due to a combination of favorable topography and climate conditions, both during and between high obliquity periods. We present several scenarios for the GLFs observed in this study and suggest that the glacial and erosional processes that affect GLF evolution are likely locale-dependent.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"129 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JE008207","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142021788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Probable Concretions Observed in the Shenandoah Formation of Jezero Crater, Mars and Comparison With Terrestrial Analogs","authors":"H. Kalucha,&nbsp;A. Broz,&nbsp;N. Randazzo,&nbsp;J. Aramendia,&nbsp;J. M. Madariaga,&nbsp;B. Garczynski,&nbsp;N. Lanza,&nbsp;L. Mandon,&nbsp;T. Fouchet,&nbsp;D. C. Catling,&nbsp;A. G. Fairén,&nbsp;L. Kivrak,&nbsp;P. J. Gasda,&nbsp;J. I. Núñez,&nbsp;E. Cloutis,&nbsp;K. P. Hand,&nbsp;J. W. Rice Jr.,&nbsp;W. W. Fischer,&nbsp;S. Maurice,&nbsp;R. C. Wiens","doi":"10.1029/2023JE008138","DOIUrl":"https://doi.org/10.1029/2023JE008138","url":null,"abstract":"<p>The Mars 2020 <i>Perseverance</i> Rover imaged diagenetic textural features in four separate sedimentary units in its exploration of the 25-m-thick Shenandoah formation at Jezero Crater, Mars, that we interpreted as probable concretions. These concretions were most abundant in the Hogwallow Flats member of the Shenandoah formation and were restricted to the light-toned, platy, sulfur-cemented bedrock at outcrop surfaces, whereas the finely laminated, darker toned, mottled and deformed strata lack concretions. The concretions also had a wide range of morphologies including concentric, oblate, urn, and spheroidal shaped forms that were not clustered, and ranged in size from ∼1 to 16 mm with a median of 2.65 mm. The elemental composition of the concretions compared to the bedrock had greater abundance of magnesium and calcium salts, silicates, and possibly hematite. We compared these Jezero Crater concretions to the geochemistry of concretions from previously published studies and from two new terrestrial analog sites (Gallup Formation, New Mexico and Torrey Pines, California). In addition, we measured organic carbon content of three terrestrial sedimentary analogs of increasing age that contain concretions (Torrey Pines (Pleistocene), Gallup Formation (∼89 Ma), and Moodies Group (∼3.2 Ga)). All measured concretions contained significant concentrations of organic carbon with the maximum organic carbon content (∼2 wt. % Total organic carbon) found in the Moodies Group concretions. Organic carbon abundances in terrestrial concretions was controlled more by the formation mechanism and relative timing of concretion development rather than deposit age. These findings suggested that concretions at Jezero Crater reflect local sites of enhanced biosignature preservation potential.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"129 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142007210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insights Into Lunar Basaltic Volcanism From Mare Domes Superposed by Ring-Moat Dome Structures (RMDSs) in Mare Tranquillitatis","authors":"Feng Zhang,&nbsp;James W. Head,&nbsp;Lionel Wilson,&nbsp;Yibo Meng,&nbsp;Christian Wӧhler,&nbsp;Dijun Guo,&nbsp;Shengli Niu,&nbsp;Roberto Bugiolacchi,&nbsp;Le Qiao,&nbsp;Yanan Dang,&nbsp;Yang Liu,&nbsp;Yongliao Zou","doi":"10.1029/2023JE007969","DOIUrl":"https://doi.org/10.1029/2023JE007969","url":null,"abstract":"<p>Mare domes (interpreted to be a type of shield volcano) represent one important endmember of a variety of volcanic edifices occurring across the volcanic plains on the Moon, whereas Ring-Moat Dome Structures (RMDSs) are interpreted to reflect the thermodynamic behavior of plain-forming mare flows during their emplacement and cooling. A comprehensive study of the direct association between mare domes and RMDSs can not only provide deep insights into their formation mechanisms but also yield key information on the nature of mantle sources. We characterized a total of 200 mare domes and more than 6,400 RMDSs within Mare Tranquillitatis using multiple sets of imagery and topography data. RMDS-bearing domes (80 out of 200) are on average larger than those hosting no RMDSs (average diameter 10.2 vs. 5.5 km) and have lower height/diameter (H/D) ratios (0.01 vs. 0.02) and flank slopes (1.2° vs. 2°). We attribute the presence of RMDSs on some domes to be due to relatively higher effusion rates forming longer thinner flows, producing favorable conditions for the formation of RMDSs. The average diameter of the RMDSs on mare domes (226 m, <i>n</i> = 1,027) appears to be slightly smaller than those located in mare plains (256 m, <i>n</i> = 527). This may be due to slope effects and that the relatively thicker off-dome part of flows undergoes a relatively higher degree inflation process, producing slightly larger RMDSs. We adapt the RMDS-formation theoretical model to shallow subcrustal magma reservoir model to account for the Tranquillitatis dome-RMDS associations.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"129 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JE007969","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141994149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Simulations of Magnetic Effects on Zonal Flows in Giant Planets","authors":"Shanshan Xue,&nbsp;Yufeng Lin","doi":"10.1029/2023JE008280","DOIUrl":"https://doi.org/10.1029/2023JE008280","url":null,"abstract":"<p>Jupiter and Saturn exhibit alternating east-west jet streams. The origin of these zonal flows has been debated for decades. The high-precision gravity measurements by the Juno mission and the grand finale of the Cassini mission have revealed that the observed zonal flows may extend several thousand kilometres deep and stop around the transition region from molecular to metallic hydrogen, suggesting the magnetic braking effect on zonal flows. In this study, we perform a set of magnetohydrodynamic simulations in a spherical shell with radially variable electrical conductivity to investigate the interaction between magnetic fields and zonal flows. A key feature of our numerical models is that we impose a background dipole magnetic field on the anelastic rotating convection. By varying the strength of the imposed magnetic field and the vigor of convection, we investigate how the magnetic field interacts with the convective motions and the convection-driven zonal flows. Our simulations reveal that the magnetic field tends to destroy zonal flows in the metallic hydrogen and suppress zonal flows in the molecular envelope, while the magnetic field may enhance the radial convective motions. We extract a quantitative relation between the magnetic field strength and the amplitude of zonal flows at the surface through our simulations, which roughly matches the observed magnetic field and zonal wind speed of Jupiter and Saturn. This discovery provides support from a new perspective for the scenario of deep convection-driven zonal winds which are confined to the molecular hydrogen layers in giant planets.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"129 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141980304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Volatile and Trace Element Storage in a Crystallizing Martian Magma Ocean","authors":"Shi J. Sim,&nbsp;Marc M. Hirschmann,&nbsp;Saswata Hier-Majumder","doi":"10.1029/2024JE008346","DOIUrl":"https://doi.org/10.1029/2024JE008346","url":null,"abstract":"<p>Immediately following core formation on Mars, the planet underwent a magma ocean phase. Volatiles released from the magma ocean fostered a primitive atmosphere which modulated heat loss from the cooling planet through the greenhouse effect. The solidification and degassing of the magma ocean are therefore coupled. In this work, we investigate two important aspects of this evolution: (a) the dynamics of melt trapping at the freezing front of the residual mantle and (b) the oxidation state during crystallization. For crystallization rates applicable to the martian magma, compaction is inefficient, leading to large fractions of melt trapped together with the crystals accumulating in the residual mantle. The H₂O content of the martian residual mantle is strongly influenced by dynamic melt trapping. Following magma ocean crystallization, up to 55.4% of the initial H₂O in the magma ocean is sequestered in the residual mantle, with the rest outgassed to the surface. Dynamic melt trapping also limits variations in trace element concentrations and fractionations. Resulting variations in important isotopic parent/daughter ratios (Sm/Nd, Lu/Hf) cannot account for all of the isotopic diversity inferred for martian basalt source regions, hence requiring alternative mechanisms. The redox state of the magma ocean exerts a strong control on the total CO₂ content of the residual mantle and the time of crystallization. Under oxidizing conditions, the residual mantle stores 0.01% of the delivered CO₂ but under the most reducing conditions we examined, the residual mantle can sequester 80.4% in the form of trapped carbonated melt and graphite/diamond.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"129 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008346","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141980336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mars' North Polar Spiral Trough Migration Paths as Revealed Through 3D Radar Mapping","authors":"Kris L. Laferriere,&nbsp;Ali M. Bramson,&nbsp;Isaac B. Smith","doi":"10.1029/2023JE007996","DOIUrl":"https://doi.org/10.1029/2023JE007996","url":null,"abstract":"<p>We present observations and maps of Mars' northern polar spiral trough migration paths (TMPs) as revealed through the 3D SHARAD (Shallow Radar) data volume, identify patterns of TMP morphology, and provide interpretations and implications of these TMPs on past climate. This data set provides additional spatial context over traditional 2D data as it allows for radargrams to be taken perpendicular to each trough strike, which minimizes distortion of migration paths due to oblique viewing geometry. Here, we present an expanded survey of trough migration and analysis of surface troughs across the north polar layered deposits. We corroborate many previous observations of trough migration such as: the general poleward and stratigraphically upward migration from the TMP initiation point; the broadly similar depth of trough initiation across the cap; regional variability in TMP morphology; and the presence of buried promontories. Our results support the presence of two generations of troughs, though we cannot confirm that the oldest generation originated deeper than ∼600 m beneath the current surface, as previously reported. Two generations of troughs suggest that climate conditions favorable for initiation of trough migration have occurred at least twice. Trough initiation occurring only in the upper ∼600 m suggests that troughs are relatively recent features in the polar cap, developing after the formation of ∼half the current cap height. The mapped TMPs provide insight into the consistency of Mars' climate during the accumulation of the past few hundred meters of ice by recording the boundary of erosion and accumulation of ice at the troughs.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"129 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JE007996","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141967136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ter-Diurnal Atmospheric Tide on Mars","authors":"Joonas Leino,&nbsp;Ari-Matti Harri,&nbsp;Robert John Wilson,&nbsp;Don Banfield,&nbsp;Mark Lemmon,&nbsp;Mark Paton,&nbsp;Jose-Antonio Rodriguez-Manfredi,&nbsp;Hannu Savijärvi","doi":"10.1029/2024JE008452","DOIUrl":"https://doi.org/10.1029/2024JE008452","url":null,"abstract":"<p>Cyclic absorption of solar radiation generates oscillations in atmospheric fields. These oscillations are called atmospheric or thermal tides, which are furthermore modified by topography and surface properties. This leads to a complex mix of sun-synchronous and non-sun-synchronous tides that propagate around the planet eastward and westward. This study focuses on analyzing the ter-diurnal component (period of 8 hr) from surface pressure observations by Mars Science Laboratory (MSL), InSight, Viking Lander (VL) 1, and VL2. General Circulation Model (GCM) results are used to provide a global context for interpreting the observed ter-diurnal tide properties. MSL and InSight have a clear and similar seasonal cycle, with local amplitude peaks at around solar longitude (Ls) 60°, Ls 130°, and Ls 320°. The amplitude peak at Ls 320° is related to the annual dust storm, while the Ls 230° dust storm is not detected by either platforms. During global dust storms, MSL, VL1, and VL2 detect their highest amplitudes. The GCM predicts the weakest amplitudes at the equinoxes, while the strongest ones are predicted in summer for both hemispheres. GCM amplitudes tend to differ from the observations but match slightly better around the aphelion season. During this time, model results suggest that the two most prominent modes are the sun-synchronous ter-diurnal tide and an eastward propagating resonantly enhanced Kelvin wave. Simulations with and without the effect of radiative heating by water ice clouds indicate the clouds may play a significant role in forcing the ter-diurnal tide during northern hemisphere summer season.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"129 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008452","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141967854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation on the Impact of Solar Flares on the Martian Atmospheric Emissions in the Dayside Near-Terminator Region: Case Studies","authors":"Lot Ram,&nbsp;Ritika Sharma,&nbsp;Diptiranjan Rout,&nbsp;Rahul Rathi,&nbsp;Sumanta Sarkhel","doi":"10.1029/2024JE008315","DOIUrl":"https://doi.org/10.1029/2024JE008315","url":null,"abstract":"<p>Solar transient events like flares can cause sudden changes in planetary plasma and neutral environment. However, there is less understanding about their impact on the Martian emissions. Here, we present an investigation of the variability of the Martian atmospheric emissions, viz. OI 130.4 nm, 135.6 nm, CO₂⁺ ultraviolet doublet (UVD), and CO Cameron band (CB) in the dayside near-terminator region during solar flare events. The two X8.2 and M6 class flares during September 2017 on Mars have been selected from existing catalogs. Using data from the imaging ultraviolet spectrograph aboard the Mars Atmosphere and Volatile EvolutioN spacecraft, we examined limb radiance profiles. We observed a significant increase in peak radiance (∼130–140 km) for major emissions with a more pronounced impact beneath the emissions peak during flares compared to quiet time. During solar flares, for 130.4 and 135.6 nm emission, the maximum deviation in radiance beneath peak approaches ∼63% and ∼123%, respectively. Whereas, for CO₂⁺ UVD and CO CB, it is ∼64% and ∼50%, respectively. Additionally, we have presented an average scenario of the dayside near-terminator (solar zenith angle ∼ 70–90°) and observed a notable trend of higher percentage deviation for atomic emissions compared to molecular emissions during flares. Further, our analysis depicts a higher percentage deviation during X8.2 compared to the M6 class flare. This study underscores that during flares, higher irradiance flux and photoelectron impact drive the airglow production processes, leading to enhanced emissions. The case studies offer a novel insight into the significant influence of the varying solar flares intensities on planetary atmospheric emissions.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"129 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141967855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Orbital Comparison of a Late Mantling Unit on Aeolis Mons With Other Erosion-Resistant Strata Explored by MSL in Gale Crater, Mars","authors":"A. Rudolph,&nbsp;B. Horgan,&nbsp;K. Bennett,&nbsp;C. Weitz,&nbsp;R. Sheppard,&nbsp;S. G. Banham,&nbsp;A. B. Bryk,&nbsp;E. Kite,&nbsp;A. Roberts,&nbsp;L. Scuderi","doi":"10.1029/2023JE008242","DOIUrl":"https://doi.org/10.1029/2023JE008242","url":null,"abstract":"<p>Previous investigations along <i>Curiosity</i>'s traverse in Gale crater have explored the relationship between orbital and in situ observations. This work aims to better understand the geologic environment of units only observable from orbit and compare them to the properties of units examined by <i>Curiosity</i>. Here, we map an erosion-resistant dark-toned mantling unit that overlies the modern topography of Aeolis Mons (informally known as Mt. Sharp) and compare this unit to two other previously mapped dark-toned resistant units, the marker band and the mound skirting unit (MSU), that have been inferred to represent different geologic environments (lacustrine and aeolian, respectively). Visible to short wave infrared spectra from the Compact Reconnaissance Imaging Spectrometer for Mars and visual images from the High Resolution Imaging Science Experiment and Context Cameras aboard the Mars Reconnaissance Orbiter are used for this comparison. Spectral data suggest a mafic composition with minor alteration, although the composition varies more with location around Mt. Sharp rather than between units. Morphologically, the mantling unit has strong similarities to the marker band based on their consistent low-albedo, erosion-resistance, and smooth appearance, contrasting with the highly variable surface texture of the MSU. We hypothesize that all three units had a similar sediment source but experienced aqueous alteration at different times: early ubiquitous cementation in a surface aqueous environment in the mantling unit and marker band versus patchy late diagenesis in the MSU. If true, these results suggest that water activity continued within the Gale crater long after the erosion of Mt. Sharp.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"129 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JE008242","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141967178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}