Journal of Geophysical Research: Planets最新文献

{"title":"Mare Basalt Thickness in the Chang'E-6 Landing Region: Insights Into Late-Stage Volcanism in the Lunar Farside South Pole–Aitken Basin","authors":"Ziyi Jia,&nbsp;Haijun Cao,&nbsp;Xuejin Lu,&nbsp;Le Qiao,&nbsp;Zongcheng Ling","doi":"10.1029/2024JE008835","DOIUrl":"https://doi.org/10.1029/2024JE008835","url":null,"abstract":"<p>Chang'E-6 probe collected lunar samples from a young mare plain in the southern Apollo basin within the South Pole–Aitken (SPA) basin on the lunar farside. By synthesizing morphological, compositional, and spectral data, we analyzed the excavation depths of craters that penetrated different basalt layers to evaluate the stratigraphy and total thickness of the mare deposits using multiple remote sensing data sets (Kaguya Multiband Imager). Results reveal that the upper Eratosthenian-aged basalt layer, approximately 79 m thick, is relatively thick in the west and gradually thins toward the east but thickens again, while the lower Imbrian-aged mare layer, around 44 m thick, exhibits an overall thinning trend from northwest to southeast. This thickness variation of the Eratosthenian-aged basalt unit is likely influenced by the formation of the nearby wrinkle ridge (∼3.2 Ga), which resulted from the cooling and contraction of the Imbrian-aged basalt unit. The ridge may have acted as a barrier, obstructing the westward flow of moderate-Ti lava that later formed the Eratosthenian-aged basalts. Both Chang'E-5 and Chang'E-6 landing regions show similarities in basalt composition and thickness; however, the Chang'E-6 zone experienced significantly smaller eruption volumes. The similar eruptive volumes between Imbrian- and Eratosthenian-aged basalts at the Chang'E-6 landing region suggest that late-stage mare volcanism in the SPA basin was likely controlled by a thin crust facilitating magma ascent and dike propagation rather than a gradual increase in eruption volume over time.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 5","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144117987","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":"Thermal Infrared Spectra of the Moon: Results From the Lucy Thermal Emission Spectrometer Observations","authors":"Philip R. Christensen,&nbsp;Victoria E. Hamilton,&nbsp;Saadat Anwar,&nbsp;Greg Mehall,&nbsp;John R. Spencer,&nbsp;Jessica M. Sunshine,&nbsp;Harold F. Levison","doi":"10.1029/2024JE008493","DOIUrl":"https://doi.org/10.1029/2024JE008493","url":null,"abstract":"<p>The Lucy Thermal Emission Spectrometer (L’TES) instrument acquired hyperspectral thermal infrared (TIR) observations of the Earth's Moon during Lucy's 2022 Earth gravity assist. L’TES covers the spectral range of 100–1,750 cm⁻¹ (100–5.8 μm) at a spectral sampling of 8.64 cm⁻¹ (Christensen et al., 2023, https://doi.org/10.1007/s11214-023-01029-y). The field of view (FOV) is 7.3-mrad, giving a spatial resolution on the Moon of 1,650 km. Seventeen high-quality spectra of the warm disk were acquired of Oceanus Procellarum that provide the first well-calibrated TIR observations of the Moon with high spectral resolution. The lunar surface emissivity was determined by modeling the surface radiance using two different methods that gave nearly identical results. The L’TES spectra have Christiansen feature (CF) maxima at 1,226 cm⁻¹ (8.15 μm), a spectral band depth of ∼0.04, and a downward slope at wavenumbers &gt;1,200 cm⁻¹ that is characteristic of &lt;100 μm particles. Comparison with Diviner 3-point spectral data (Greenhagen et al., 2010, https://doi.org/10.1126/science.1192196) shows excellent agreement in the CF location and band shape. The L’TES spectra closely match several lunar soil laboratory spectra (Donaldson-Hanna et al., 2017, https://doi.org/10.1016/j.icarus.2016.05.034), providing excellent ground truth for the L’TES observations, validating the L’TES data processing, and demonstrating that high-spatial and spectral resolution TIR data would provide a powerful tool for remote compositional mapping. The L’TES nightside observations accurately derived surface temperatures at 110 K, even when the Moon only filled 10% of the FOV, confirming that L’TES will accurately determine the cold Trojan asteroid temperatures.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 5","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008493","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144117858","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":"Inferring Fireball Velocity Profiles and Characteristic Parameters of Meteoroids From Incomplete Data Sets","authors":"Eloy Peña-Asensio,&nbsp;Maria Gritsevich","doi":"10.1029/2024JE008382","DOIUrl":"https://doi.org/10.1029/2024JE008382","url":null,"abstract":"&lt;p&gt;Extracting additional information from old or incomplete fireball data sets remains a challenge. To address missing point-by-point observations, we introduce a method for estimating atmospheric flight parameters of meteoroids using metaheuristic optimization techniques. Using a fireball catalog from the European Fireball Network (EN), we reconstruct velocity profiles, meteoroid bulk densities, mass loss rates, and ablation and ballistic coefficients, based on the initial and terminal points' height, velocity, and mass with the purely dynamical &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;α&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $alpha $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;-&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;β&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $beta $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; model. Additionally, the method's performance is compared to the Meteorite Observation and Recovery Project (MORP) derived fits, confirming the robustness of the computed parameters for objects with asteroidal compositions. Our findings show that &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;α&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $alpha $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;-&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;β&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $beta $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; model yields parameters consistent with the photometric and dynamic mass estimates in the EN catalog for &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;P&lt;/mi&gt;\u0000 &lt;mi&gt;E&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${P}_{E}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; type I events. However, in the implementation proposed here, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;α&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $alpha $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;-&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;β&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $beta $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; model encounters limitations in accurately representing the final deceleration of more fragile high-velocity meteoroids. This is likely due to challenges in representing complex fragmentation processes by fitting only two points, even when initial and terminal residuals are minimal. The retrieved &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;α&lt;/mi&gt;\u0000 ","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 5","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008382","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144117859","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":"The Sporadic Fluvial Regime of Pliva Vallis, the Outlet Valley of Jezero Crater Lake, Mars","authors":"J. Villette,&nbsp;N. Mangold,&nbsp;E. S. Kite,&nbsp;S. J. Conway,&nbsp;L. Le Deit","doi":"10.1029/2024JE008862","DOIUrl":"https://doi.org/10.1029/2024JE008862","url":null,"abstract":"<p>In situ and orbital observations have suggested that Jezero crater (field site for the Mars 2020 Perseverance rover) once hosted a paleolake fed by two inlet valleys. An outlet valley, Pliva Vallis, is present on the eastern rim of the crater and raises the question of whether the lake system operated as an open basin or as a closed basin system with one or more overflow events. To tackle this uncertainty, we present a detailed morphological study of Pliva Vallis, using digital elevation models and imagery. The atypical morphology of the valley, including reincised fluvial layered deposits, a perched valley, and bedrock incision terraces, led us to interpret that Pliva Vallis was formed by discontinuous and episodic flows rather than from a steady outlet river. These observations allowed us to infer at least four main breach episodes and propose a new scenario for the evolution of the lake system over time. We give a minimum estimate of the duration of these overflow events using a 0-D model, simulating a valley formation by breach erosion and lake overflow. Modeling results suggest that each flood event causing a part of the incision of the outlet valley would not have lasted for more than a few weeks, and some may have lasted only a few days. These time scales are consistent with our morphological interpretation that the outlet valley was carved by discontinuous and temporary flows. In this scenario, Jezero lake was predominantly a closed basin, spilling over episodically in at least four breach events.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 5","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008862","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144091670","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":"Compositional and Morphological Variations of Effusive Lava Flows and Explosive Pyroclastic Deposits at the Caldera-Forming Gardner Shield Volcano on the Moon","authors":"Henal V. Bhatt,&nbsp;Timothy D. Glotch,&nbsp;Edgard G. Rivera-Valentín,&nbsp;Hunter Vannier,&nbsp;Heather M. Meyer","doi":"10.1029/2024JE008692","DOIUrl":"https://doi.org/10.1029/2024JE008692","url":null,"abstract":"<p>We identified a ∼31 km diameter caldera with a well-developed ring fault and ring dike structure at the Gardner shield volcano. Using Chandrayaan-1 Moon Mineralogy Mapper (M³) and Lunar Reconnaissance Orbiter (LRO) Diviner data, we investigated 15 effusive flow units and an explosive unit. Spectral analysis revealed compositional similarities between effusive and explosive eruptions, indicating a single sourced magmatic eruption. Detailed hyperspectral and multispectral analyses (visible, near-infrared, thermal infrared, and radar) indicate the presence of explosive pyroclastic material in the central part of the shield. We identified key morphological structures at the Gardner shield, including three major faults, the caldera's ring fault and ring dike structure, subsidence and resurgence crustal blocks, a graben, a parasitic cone, and extended lineaments beyond the previous work. Our analysis indicates that the well-developed Gardner caldera exhibits lower subsidence compared to Earth's calderas, likely due to the Moon's lower gravity and lower crustal density. These surficial structures preserve the evidence of subsurface magmatic chamber dynamics, making the Gardner shield a unique location for understanding the thermophysical evolution of a central vent shield regime on the Moon. We describe six evolutionary stages, evidenced by multiple volcano-tectonic structures, two distinct eruption styles, and the shield's relationship with the subsurface magmatic chamber, revealing a thermophysical evolution of a central-vent polygenetic shield volcano on the Moon, following a formation mechanism similar to those observed in the shield volcanoes on Earth and Mars.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 5","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144091668","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":"Impacts of Dry Deposition Processes With Resolved Dust Particle Sizes on Simulating the Martian Dust","authors":"Lulu Li,&nbsp;Chun Zhao,&nbsp;Claire E. Newman,&nbsp;Yongxuan Zhao,&nbsp;Jiawang Feng,&nbsp;Tao Li,&nbsp;Chengyun Yang,&nbsp;Yingxi Yue","doi":"10.1029/2024JE008616","DOIUrl":"https://doi.org/10.1029/2024JE008616","url":null,"abstract":"<p>Mars, characterized as a “desert” planet with little water vapor, primarily relies on dry deposition for dust removal. Although these processes include gravitational sedimentation, turbulent transfer, Brownian diffusion, impaction, interception, and rebound, most current models consider only gravitational sedimentation. To have a more comprehensive understanding of the effects of Martian dust removal processes, a physics-based scheme of dry deposition processes with resolved dust particle sizes is implemented in the Mars Weather Research and Forecasting (MarsWRF) model. Results show that the size-resolved dry deposition scheme significantly increases the dry deposition velocity, with the maximum difference (over 0.024 m/s) occurring at 0.884 μm size bin. This enhanced removal efficiency leads to an increase of 0.4 μm in the effective radius of airborne dust throughout the year and a reduction of approximately 0.09 in dust opacity, particularly in the northern high latitudes during autumn and winter, compared to the simulation that only considers a size-resolved gravitational sedimentation scheme. The overestimation of low-level atmospheric temperature in the mid-to-low latitudes, excluding near-surface regions between <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>20</mn>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> $20mathit{{}^{circ}}$</annotation>\u0000 </semantics></math> and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>60</mn>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> $60mathit{{}^{circ}}$</annotation>\u0000 </semantics></math>N, during <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>L</mi>\u0000 <mi>s</mi>\u0000 </msub>\u0000 <mo>=</mo>\u0000 <mrow>\u0000 <mrow>\u0000 <mn>230</mn>\u0000 <mo>−</mo>\u0000 <mn>250</mn>\u0000 </mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> ${L}_{s}=230-250mathit{{}^{circ}}$</annotation>\u0000 </semantics></math> (considered as peak-dust phase) is partially corrected, with a correction of up to 1 K compared to the single-particle size simulation and up to 5 K compared to the size-resolved sedimentation-only simulation, bringing it closer to MCS observations. Additionally, the size-resolved dry deposition simulation reduces the condensation rate of atmospheric CO₂ and the thickness of the northern CO₂ ice cap, aligning better with Viking Lander observations during northern winter and spring than the size-resolved sedimentation-only simulation.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 5","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144091669","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":"The Chang’E-6 Landing Region: Geologic Context, Mare Basalt, and Regolith Properties","authors":"Bojun Jia,&nbsp;Wenzhe Fa,&nbsp;Mingwei Zhang","doi":"10.1029/2025JE009018","DOIUrl":"https://doi.org/10.1029/2025JE009018","url":null,"abstract":"<p>Chang’E-6 (CE-6) is the first lunar farside sample-return mission. It landed in an Eratosthenian mare basalt unit within the South Pole-Aitken basin (SPA) and returned 1,935.3 g samples. These returned samples can address a wide range of fundamental questions about the Moon, including the nature of farside volcanism and mantle, the stratigraphy and evolution of the SPA terrain, the impact flux, chronology, and space weathering process of the lunar farside. This study investigates the geological context, mare basalt, and regolith properties of the CE-6 landing region using multi-source remote sensing observations. The size and spatial distributions of the penetrating craters and buried craters reveal that the thickness of the surface Eratosthenian basalt in most regions ranges from <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>30–60 m, and a layer of Imbrian basalts with a thickness of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>90–120 m lies beneath. Morphology and rock population of small fresh craters within a 3 km radius of the landing site indicate a 2–10 m thick regolith layer with a median thickness of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>3 m. Combined analysis of infrared and radar observations suggests a finer regolith at the landing site, with fewer meter-scale rocks but more centimeter- to decimeter-scale rocks compared with Chang’E-5 landing site. The surface features in the mare unit suggest that the regolith at the landing site may contain exotic ejecta primarily from Chaffee S, Vavilov, Lovell, and White craters, potentially including SPA melt and mantle materials. These findings improve the understanding of volcanic activity and regolith evolution at the landing site, and further provide foundations for subsequent laboratory analysis of the returned samples.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 5","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144074471","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":"A Simulation Study of Martian Airglow Emission Response to the X8.2 Solar Flare on 10 September 2017","authors":"Zerui Liu,&nbsp;Jiuhou Lei,&nbsp;Maodong Yan,&nbsp;Tong Dang","doi":"10.1029/2024JE008878","DOIUrl":"https://doi.org/10.1029/2024JE008878","url":null,"abstract":"&lt;p&gt;During the solar flare, the planetary upper atmosphere and ionosphere are rapidly impacted, and the airglow emission intensity can be significantly enhanced. Previous studies have been carried out on the variation of Martian airglow emissions using the Imaging Ultraviolet Spectrograph instrument aboard the Mars Atmosphere Volatile EvolutioN mission. However, the underlying mechanisms responsible for Martian emission intensity during solar flare events remain to be addressed. In this study, we explore the variation of the emission intensity caused by the X8.2 solar flare on 10 September 2017, using photoelectron transport model, focusing on two typical emission spectra—&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mtext&gt;CO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CO}}_{2}^{+}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; Ultraviolet doublet (UVD) and &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mtext&gt;CO&lt;/mtext&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $text{CO}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; Cameron band. We show the comparison of the simulated and observed emission intensity and find that the variation trend with altitude of simulated limb intensity is in agreement with the observation. In both the simulated and observed results, a sub-peak in the limb intensity around 100 km is observed, attributed to the photoelectron impact process. Additionally, the photoelectron impact process responds more strongly to the solar flare than the photon impact process, and leads to a sharper sub-peak at the peak flare period. Furthermore, the photon impact process, causing the different response of &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mtext&gt;CO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;B&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msup&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;Σ&lt;/mi&gt;\u0000 &lt;mi&gt;u&lt;/mi&gt;\u0000 &lt;mo&gt;+&lt;/mo&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CO}}_{2}^{+}left({mathrm{B}}^{2}{{Sigma }}_{mathrm{u}}^{+}right)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; and &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mtext&gt;CO&lt;/mtext&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;mn&gt;3&lt;/mn&gt;\u0000 &lt;/msup&gt;\u0000 ","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 5","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144074545","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":"Paleo-Scours Within the Layered Sulfate-Bearing Unit at Gale Crater, Mars: Evidence for Intense Wind Erosion","authors":"Amelie L. Roberts,&nbsp;Sanjeev Gupta,&nbsp;Steven G. Banham,&nbsp;Aster Cowart,&nbsp;Lauren A. Edgar,&nbsp;William Rapin,&nbsp;William E. Dietrich,&nbsp;Joel M. Davis,&nbsp;Edwin S. Kite,&nbsp;Gwénaël Caravaca,&nbsp;Claire A. Mondro,&nbsp;Patrick J. Gasda,&nbsp;Jeffrey R. Johnson,&nbsp;Stéphane Le Mouélic,&nbsp;Deirdra M. Fey,&nbsp;Alexander B. Bryk,&nbsp;Gerhard Paar,&nbsp;Emma R. A. Harris,&nbsp;Abigail Fraeman,&nbsp;Ashwin R. Vasavada","doi":"10.1029/2024JE008680","DOIUrl":"https://doi.org/10.1029/2024JE008680","url":null,"abstract":"<p>The surface of modern Mars is largely shaped by wind, but the influence of past wind activity is less well constrained. Sedimentary rocks exposed in the lower foothills of Aeolis Mons, the central mound within Gale crater, record a transition from predominantly lacustrine deposition in the Murray formation to aeolian deposition in the Mirador formation. Here, we report a series of enigmatic decameter-wide, concave-up scour-and-fill structures within the Mirador formation and discuss their formation mechanisms. Using panoramic images of stratigraphy exposed in cliff faces acquired by the <i>Curiosity</i> rover, we map the extent, distribution and orientation of the scour-and-fill structures and document the sedimentary facies within and surrounding these structures. The scours are grouped into two classes: (A) scours with a simple, symmetric morphology and light-toned, draping infill; and (B) scours with lateral pinching and dark-toned infill. We find that the scour-enclosing environment is composed of planar, even-in-thickness laminations with a pin-stripe pattern which we interpret as wind-ripple strata formed within an aeolian sandsheet environment. Class B contains cm-scale cross-bedding and a wing-shaped feature making this scour-and-fill structure consistent with fluvial processes. We interpret scour fill of class A as an aeolian infill due to similarities with the surrounding sandsheet strata. The broad morphologies and distribution of class A are also consistent with the geometry of blowout structures formed by localized, enhanced wind deflation. These paleo-blowout structures occur clustered within the same stratigraphic interval, which may imply that they record an interval of intensified wind activity at Gale crater.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 5","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008680","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143944808","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":"The Link Between Subsurface Rheology and Ejecta Mobility: The Case of Small New Impacts on Mars","authors":"A. J. Sokolowska,&nbsp;G. S. Collins,&nbsp;I. J. Daubar,&nbsp;M. Jutzi","doi":"10.1029/2024JE008561","DOIUrl":"https://doi.org/10.1029/2024JE008561","url":null,"abstract":"<p>The dynamics of crater ejecta are sensitive to the material properties of the target, much like the crater size and morphology. We isolate and quantify the effect of target properties on the ejecta mobility (EM) - the maximum radial extent of ejecta scaled by the crater radius. We compile geologically motivated subsurface structures based on data gathered by orbiters and landers. Those structures arise from varying properties of materials in single layers (strength, composition, porosity); the thickness of top regolith cover; and the sequence and thicknesses of 3–4 stacked layers. We realize 2D simulations with the iSALE shock physics code which result in a 50 m diameter crater (an analog of new craters formed in the period of spacecraft observation). We find that varied subsurface rheologies result in EM numbers with a wide range of values between 7 and 19. Some subsurface models can result in a similar EM, and some have distinct EMs, which shows potential for using this quantity as a new diagnostic of target properties. We also show that ejecta dynamics are sensitive not only to the material in the excavation zone but also at much greater depths than commonly assumed (at least 1–2 crater radii). EM also depends on both material properties and layering: the impedance contrast governs the nature of wave propagation, while the layer depth controls the timing of the shock wave reflection. Detailed studies of EM thus have promise for unveiling shallow subsurface rheologies on many Solar System bodies in the future.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 5","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008561","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143944479","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}