Journal of Geophysical Research: Planets最新文献

{"title":"Ferromagmatic Intrusions on Asteroid (16) Psyche May Be Magnetized","authors":"Samuel W. Courville,&nbsp;Hannah R. Sanderson,&nbsp;Carver J. Bierson,&nbsp;Linda T. Elkins-Tanton,&nbsp;Rona Oran,&nbsp;Joseph G. O'Rourke,&nbsp;Christopher T. Russell,&nbsp;Benjamin P. Weiss,&nbsp;David A. Williams","doi":"10.1029/2025JE009031","DOIUrl":"10.1029/2025JE009031","url":null,"abstract":"<p>NASA's Psyche mission will arrive at the metal-rich asteroid (16) Psyche in 2029. The mission will test whether (16) Psyche is a remnant of a melted, differentiated planetesimal that formed a molten iron metallic core. Previous studies have suggested that a molten metallic core fluid could erupt volcanically, explaining the high metal content of (16) Psyche's surface. Here we describe an origin story for (16) Psyche using thermal and compositional evolution modeling that outlines when ferrovolcanism could occur. We highlight how Psyche's Magnetometer could detect remanent magnetization associated with mantle intrusions of the core metal.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JE009031","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145128958","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":"Comprehensive Analysis of the Alteration of Tyrrhena Terra: Implications for Source-to-Sink Processes on Mars","authors":"Yuchun Wu,&nbsp;Nicolas Mangold,&nbsp;Yang Liu,&nbsp;John Carter,&nbsp;Xing Wu,&nbsp;Lu Pan,&nbsp;Qian Huang,&nbsp;Chaolin Zhang,&nbsp;Keyi Li,&nbsp;Yongliao Zou","doi":"10.1029/2025JE008951","DOIUrl":"10.1029/2025JE008951","url":null,"abstract":"<p>Tyrrhena Terra, a region located in the cratered highlands between Hellas and Isidis Planitia on Mars, is distinguished by its extensive presence of hydrated minerals. Using 542 hyperspectral images from the Compact Reconnaissance Imaging Spectrometer for Mars, we detected 252 exposures of hydrated minerals. This region is characterized by a widespread distribution of Fe/Mg-smectites/vermiculites and chlorite, with additional detections of Al-phyllosilicates, zeolites, prehnite, hydrated silica, and carbonates. We classified the mineralogical detections in classes of impact crater diameters, locations in craters, and for those <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&gt;</mo>\u0000 </mrow>\u0000 <annotation> ${ &gt;} $</annotation>\u0000 </semantics></math>20 km, their relative degradation stages. We found that craters <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&lt;</mo>\u0000 </mrow>\u0000 <annotation> ${&lt; } $</annotation>\u0000 </semantics></math>10 km display a lower mineral diversity than larger ones. In contrast, craters <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&gt;</mo>\u0000 </mrow>\u0000 <annotation> ${ &gt;} $</annotation>\u0000 </semantics></math>20 km display a high mineral diversity, especially in central peaks, suggesting a strong influence of hydrothermal processes and deep excavation. Among this diameter range, fresh, young craters exhibit a much higher mineral diversity than degraded, old craters. Fe/Mg-phyllosilicates are dominant in the latter, as well as in sedimentary units of topographically low areas. These results indicate a long-term alteration cycle in the most ancient period, where the initial, diverse hydrated minerals—formed through exhumation and/or hydrothermal circulation within large impacts—were subsequently transformed by surface weathering and/or buried, dissolved, or eroded away by other post-impact processes, then transported and deposited in lowlands by fluvial erosion. Although Tyrrhena Terra is dominated by impact-related hydrated mineral detections, our study shows that the overprint of Noachian age weathering is visible within these detections.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144773709","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":"Mineralogical and Chemical Mapping of Martian Meteorite SaU 008 Using Deep UV Raman and Fluorescence Spectroscopy on Earth and Mars","authors":"Joseph Razzell Hollis,&nbsp;Kelsey Moore,&nbsp;Marc Fries,&nbsp;Cindy Broderick,&nbsp;Yannick Buret,&nbsp;Rohit Bhartia,&nbsp;Teresa Fornaro,&nbsp;Trevor Graff,&nbsp;Kevin P. Hand,&nbsp;Keyron Hickman-Lewis,&nbsp;Ryan Jakubek,&nbsp;Carina Lee,&nbsp;Francis M. McCubbin,&nbsp;Richard V. Morris,&nbsp;Ashley Murphy,&nbsp;Sunanda Sharma,&nbsp;Caroline Smith,&nbsp;Andrew Steele,&nbsp;Kyle Uckert","doi":"10.1029/2024JE008826","DOIUrl":"10.1029/2024JE008826","url":null,"abstract":"<p>The NASA Mars 2020 mission Perseverance rover carries a piece of Martian meteorite Sayh al Uhaymir (SaU) 008 as part of the calibration payload for the SHERLOC science instrument. We report SHERLOC observations of the SaU 008 flight piece over the first 1,000 sols of the mission and compare them to measurements done prior to launch, showing consistent detection of the same deep-ultraviolet (DUV) Raman and fluorescence signatures in the same locations. Co-located X-ray fluorescence (XRF) and DUV mapping of a reference SaU 008 piece on Earth confirm that the meteorite is comprised of an igneous mineral matrix consistent with shergottite, rich in olivine, maskelynite, and Fe-Mg pyroxenes detectable by SHERLOC. Terrestrial weathering features consist of fractures and vugs filled with Ca-carbonate. Fluorescence mapping reveals two major signatures: (a) broad-spectrum fluorescence present throughout the igneous matrix but strongest in weathering features, attributed to organic material, and (b) narrow-band 340 nm fluorescence spatially associated with ∼48 ppm cerium in &lt;100 μm Ca-phosphate grains. Raman revealed organic material in both the igneous matrix and terrestrial carbonate in the form of macromolecular carbon (MMC) with defect and graphitic bands at ∼1,380 and ∼1,600 cm⁻¹ respectively. Raman band parameters suggest that MMC associated with terrestrial weathering is less thermally mature, most likely the result of chemical alteration after landing on Earth. This study serves as a demonstration of SHERLOC's capabilities when supported by co-located XRF data from PIXL and suggests that SHERLOC can detect Ce in phosphate minerals at concentrations as low as 4 ppm.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008826","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144782529","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 Effect of Mars Impact Crater Topography on Seismic Signals","authors":"J. Charoensawan,&nbsp;L. Adam,&nbsp;K. van Wijk,&nbsp;L. Margerin,&nbsp;K. Miljkovic,&nbsp;C. Nunn","doi":"10.1029/2024JE008440","DOIUrl":"10.1029/2024JE008440","url":null,"abstract":"<p>Meteorite impacts on Mars result in seismic recordings with relatively small surface wave amplitudes compared to body wave amplitudes, unlike what is generally observed in earthquakes. Here, we test with numerical modeling whether Mars' topography could be responsible for the preferential attenuation of surface waves. We use a spectral element method to simulate 3D seismic wave propagation from impact events. The model topography is based on Mars' digital elevation model, and the crustal structure is based on published works. Our results show that surface waves encountering a crater lose energy proportionally to the crater depth via scattering because the surface waves are partially converted to body waves and scatter out of the original direction of propagation. The energy loss from scattering can be recovered through multiple scattering, but the result is a net loss. The multiply scattered surface waves from distant craters arrive late, adding energy to the recorded coda waves. Body waves excited by impacts, after reflection in the subsurface, arrive at steep incidence angles on the seismometer and therefore, are almost unaffected by topography. The difference between topographic scattering of body and surface waves could explain the weak or total lack of surface waves recorded by InSight's seismometer.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008440","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144773708","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":"Utilization of X-Ray Computed Tomography During the Preliminary Examination of Unopened Apollo Drive Tube Samples 73001 and 73002","authors":"Scott A. Eckley,&nbsp;Ryan A. Zeigler,&nbsp;Richard A. Ketcham,&nbsp;David Edey,&nbsp;Romy D. Hanna,&nbsp;Juliane Gross,&nbsp;Evan W. O’Neal,&nbsp;Francis M. McCubbin,&nbsp;Charles K. Shearer,&nbsp;the ANGSA Science Team","doi":"10.1029/2024JE008583","DOIUrl":"10.1029/2024JE008583","url":null,"abstract":"<p>Double drive tube 73001/2 was collected on the Light Mantle Deposit in the Taurus-Littrow Valley by Apollo 17 astronauts. It is a 4-cm diameter core that sampled up to 70 cm deep in a lunar landslide at the base of the North Massif. NASA kept these samples pristine and untouched in anticipation of advanced future analytical techniques, such as high-resolution X-ray computed tomography (XCT). Double drive tube 73001/2 was selected to be studied as part of the Apollo Next Generation Sample Analysis (ANGSA) program and was opened in November 2019 (73002) and February 2022 (73001). We discuss how XCT was utilized during the preliminary examination of these samples. This technique, which was unavailable the last time an Apollo drive tube was opened (1993), provides a three-dimensional (3-D) image of the interior of opaque objects. Prior to opening, high-resolution scans were collected of the full length of both cores, providing a novel 3-D archive of the intact lunar regolith. After opening, 352 &gt; 4 mm particles were individually bagged and scanned, allowing for their lithological classification. We provide an example of the robustness of the individual particle data by analyzing ilmenite crystals (<i>n</i> = 350) in fourteen high-Ti basalt particles. Our results show that ilmenite generally has highly anisotropic shapes and can take on various external morphologies, indicating that 73001/2 likely sampled several lunar basalt flows. This paper illustrates the utility of XCT for curatorial and scientific purposes during ANGSA and demonstrates its value for future sample return missions.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144767340","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":"3D and 2D Clast Analysis of Apollo 17 Core Sample 73002: Insights Into the Light Mantle Dynamics and Regolith Reworking","authors":"G. Magnarini,&nbsp;T. M. Mitchell,&nbsp;P. M. Grindrod,&nbsp;S. K. Bell,&nbsp;K. H. Joy,&nbsp;S. A. Eckley,&nbsp;R. A. Zeigler,&nbsp;H. H. Schmitt,&nbsp;C. Shearer,&nbsp;the ANGSA Science Team","doi":"10.1029/2024JE008422","DOIUrl":"10.1029/2024JE008422","url":null,"abstract":"<p>The Light Mantle deposit in Taurus-Littrow Valley, Apollo 17 landing site, represents the only extraterrestrial landslide to have ever been studied in situ. The origin and hypermobility of the Light Mantle remain debated. A core sample of the Light Mantle was collected by Apollo 17 astronauts and kept sealed awaiting for advanced imaging and analytical techniques to be available in the future. The core, made up of two samples, was recently opened as part of the NASA Apollo Next Generation Sample Analysis initiative. The availability of the core for study represents an unprecedented opportunity to investigate the structures of the Light Mantle at previously unsampled depths. In this work, we used high-resolution X-ray computed tomography scans and high-resolution scans of thin sections of the upper 20 cm of the core, sample 73002. We conducted 3D clast-size analysis and investigation of clast morphological fabric. Our results (a) suggest the absence of large clasts (&gt;1 cm) in the uppermost 5 cm, consistent with the reworked regolith layer identified in previous studies of other lunar samples and (b) show the presence of clast-cortex aggregates, which are considered evidence of granular flow dynamics during the Light Mantle emplacement. Our work represents the first study to conduct a 3D clast analysis of a lunar core sample. As such, it constitutes an important step in showing the novel information that can be extracted. Moreover, it presents a potential workflow for studying lunar core samples that will be collected during future missions to the Moon.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008422","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144758486","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":"Constraining the Source Craters of Apollo Impact Melts","authors":"A. M. Blevins,&nbsp;D. A. Minton,&nbsp;Y. H. Huang,&nbsp;J. Du,&nbsp;M. M. Tremblay,&nbsp;C. I. Fassett","doi":"10.1029/2025JE009137","DOIUrl":"10.1029/2025JE009137","url":null,"abstract":"<p>Interpreting the age distribution of Apollo samples to determine the early bombardment history of the Moon has been fraught with controversy, and the question of how much material from large impact basins such as Imbrium is present in the Apollo sample collection remains unresolved. Here, we model impact melt production and transportation over lunar history to estimate the amount of melt that each basin should have contributed to the Apollo 14–17 sites. Our model results suggest that Imbrium contributes significantly to all four studied Apollo sites, but also that each site should contain more impact melt from basins older than Imbrium compared to what has been interpreted in the Apollo sample collection. We then use Bayesian inference to evaluate possible correlation between specific basins and groups of Apollo impact melt samples. We find that in every simulation, there are only a few basins sampled, but the specific basins (other than Imbrium) are different for each simulation. This suggests that most basins were not sampled in the suite of Apollo impact melts. Using a combination of numerical models and Bayesian statistics, we define four possible scenarios for the timing of basin emplacement. The impact flux for these scenarios varies from a smooth decline to a terminal “cataclysm.” The behavior of impacts in the time before Imbrium remains unconstrained, and specific samples are needed to better understand this period in lunar history.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JE009137","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144758525","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":"Geological History of the Dichotomy in the Southern Utopia Planitia of Mars","authors":"Tengfei Zhang,&nbsp;Jun Huang,&nbsp;Le Wang,&nbsp;Lukas Wueller,&nbsp;Wajiha Iqbal,&nbsp;Xiaozhong Ding,&nbsp;Long Xiao,&nbsp;Harald Hiesinger","doi":"10.1029/2025JE008931","DOIUrl":"10.1029/2025JE008931","url":null,"abstract":"<p>The Martian crustal dichotomy represents a fundamental geological boundary, separating the ancient Noachian highlands in the south from the relatively younger lowlands to the north, which may host sediments derived from a putative northern ocean. To investigate the tectonic and hydrologic evolution of this transition, we produced a high-resolution geologic map of the southern Utopia Planitia region (5°–30°N, 105°–115°E), identifying 20 stratigraphic units grouped into highland, transitional, lowland, Amenthes region, and impact-related categories. Chronostratigraphic constraints based on crater size-frequency distributions and cross-cutting/super-positional relationships allow division of the regional geologic history into five stages, encompassing two major extrusive episodes, two regional volcanic pulses, and one intrusive event. Wrinkle ridges concentrated in the central and southern mapping areas reflect compressional stresses likely associated with these volcanic events (e.g., Watters, 1988, https://doi.org/10.1029/jb093ib09p10236; Yin et al., 2023, https://doi.org/10.26464/epp2023031), suggesting that magmatic activity was a dominant driver of Noachian–Hesperian tectonic evolution. In contrast, Hesperian and Amazonian units in the northern region are interpreted as water-related deposits, consistent with emplacement in a volatile-rich environment. Among these, the AHul₂ unit satisfies both engineering and scientific criteria for landing, highlighting it as a favorable site for China's Tianwen-3 sample return mission. This study refines our understanding of the geological evolution across the dichotomy boundary and informs future exploration strategies.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144740498","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":"Constraints on the Feasibility of Ferrovolcanism on Asteroid 16 Psyche","authors":"J. J. Jorritsma,&nbsp;W. van Westrenen","doi":"10.1029/2024JE008811","DOIUrl":"10.1029/2024JE008811","url":null,"abstract":"<p>Asteroid 16 Psyche's surface appears to be highly metallic, but its bulk density suggests a silicate-rich interior. Ferrovolcanism has been suggested to explain how a silicate-rich body could develop a metallic surface. This requires trapping of light elements bearing iron-rich metallic melt in a core solidifying from the outside inwards. The buoyancy of the lighter melt must then generate sufficient pressure to carry metal melt through the mantle and cover the surface. Here, we test whether sufficient pressure could have been generated on 16 Psyche in different scenarios. Core size, light element partitioning between mantle and core, and silicate mass loss are calculated for three meteoritic bulk compositional models (H-chondrite, EH-chondrite and mesosiderite) based on mantle density and mantle porosity combinations. The resulting core compositions are used to calculate excess pressure. Mantle density and porosity combinations leading to ferrovolcanism are constrained for each bulk composition. Iron-rich bulk compositions with low light element abundances are favored. Mesosiderite bulk composition is most conducive to producing ferrovolcanism but does not naturally fit the ferrovolcanism framework. Primitive compositions are favored as the timing of ferrovolcanism is tied to the earlier stages of solar system formation. H-chondrite model scenarios may produce ferrovolcanism but require high amounts of mass loss to be considered as a building block for Psyche. EH-chondrite model scenarios are chemically not conducive to producing ferrovolcanism. Both confirmation and rejection of the ferrovolcanism hypothesis by upcoming observations from NASA's Psyche mission can therefore provide key new constraints on 16 Psyche origin and evolution scenarios.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008811","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144740499","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 Full Diurnal Cycle of Mars Water-Ice Cloud Optical Depth in EMIRS Observations","authors":"Samuel A. Atwood,&nbsp;Michael D. Smith,&nbsp;Michael J. Wolff,&nbsp;Christopher S. Edwards","doi":"10.1029/2025JE008961","DOIUrl":"10.1029/2025JE008961","url":null,"abstract":"<p>Improvements to analyses of Martian thermal infrared spectra observed by the Emirates Mars Infrared Spectrometer (EMIRS) allow for retrieval of water-ice cloud optical depth, <i>τ</i>_ice, across the full diurnal cycle at Mars. Using observations spanning nearly two Martian years, we find a persistent pattern of higher nighttime cloud abundance compared to daytime values, with regular peaks in <i>τ</i>_ice occurring in both morning and evening hours. During the colder aphelion season when the low-latitude aphelion cloud belt forms, zonal mean optical depths ranged from maxima of ∼0.5 during the morning peak to minima of ∼0.15 near midday. Averaged across the full data set, nighttime <i>τ</i>_ice values were approximately twice the optical depth at the midday minimum. The morning peak in cloud abundance tended to occur near a solar incidence angle of 75° across a range of latitudes and seasons. These diurnal patterns were generally consistent with modeled influences of atmospheric thermal tides on cloud formation conditions. Spatial differences in the distribution of clouds were noted across the diurnal cycle. Volcano clouds formed near midday and increased in optical depth through the afternoon and into the evening. At night, late evening clouds were observed more broadly across low-latitude regions, while morning clouds were more concentrated over the Tharsis region. The broad spatial and temporal coverage of these results enables new model comparisons against observations of <i>τ</i>_ice across the full diurnal cycle, and advances our understanding of water-ice cloud development and its role in the Mars climate system.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144725726","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}