Journal of Geophysical Research: Planets最新文献

{"title":"Mg-Spinel Distribution in South Pole-Aitken (SPA) Basin: Spatial Distribution, Geologic Context and Spectral Characterization","authors":"Garima Sodha,&nbsp;Deepak Dhingra","doi":"10.1029/2024JE008809","DOIUrl":"10.1029/2024JE008809","url":null,"abstract":"<p>The spatial distribution of Mg-spinel lithology at South Pole-Aitken (SPA) basin is revealed by systematic mineralogical survey along the basin rings. We report Ingenii-Thomson region as a Mg-spinel anomaly, having the largest number of exposures based on newly identified and previously reported occurrences on the Moon. The timing of Mg-spinel formation is constrained by using SPA impact as a key geological time marker. Post-SPA origin of this lithology is favored in this region due to the general lack of pervasive Mg-spinel occurrences along basin rings, being the deepest exposures of the pre-SPA crust. Our detailed mineralogical analyses also highlight several detections of Mg-spinel lithology exhibiting weak 1,000 nm absorption band, emphasizing the need for a detailed analysis of such locations. Collectively, these salient findings have important implications for understanding the compositional diversity of Mg-spinel lithology, refinement of the formation models and determining the role of Mg-spinel lithology in the lunar crustal evolution.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144927379","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":"JunoCam Observations of Io","authors":"M. A. Ravine,&nbsp;C. J. Hansen,&nbsp;M. A. Caplinger,&nbsp;P. M. Schenk,&nbsp;L. Lipkaman Vittling,&nbsp;D. J. Krysak,&nbsp;J. E. Perry,&nbsp;D. A. Williams,&nbsp;J. Radebaugh,&nbsp;M. Pettine,&nbsp;J. T. Keane,&nbsp;A. G. Hayes,&nbsp;J. A. Rathbun,&nbsp;R. M. Lopes,&nbsp;S. J. Bolton","doi":"10.1029/2024JE008924","DOIUrl":"10.1029/2024JE008924","url":null,"abstract":"<p>During multiple <i>Juno</i> encounters with Io in 2023 and 2024, the spacecraft's imaging system, JunoCam, acquired approximately one hundred images of Io. These images have a range of scales down to 1 km per pixel, and covered more than half of Io's surface, including the previously poorly resolved northern and southern polar regions. Some of the highest resolution images were acquired of Io's nightside, illuminated by Jupiter-shine. Here we provide an overview of the JunoCam Io data set and discuss the peculiarities of JunoCam's “pushframe” imaging. Using JunoCam's high resolution coverage of the northern polar region, we have developed an improved geologic map of this previously poorly resolved area, and estimated the heights of 16 previously unidentified or poorly imaged mountains. In the higher resolution images, 14 new or modified plume deposits were identified, as were at least 20 probable new lava flows. Eight “Prometheus-type” volcanic plumes were identified, five of which were associated with areas showing flow-like surface changes.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008924","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144927380","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":"Testing the Fidelity of Paleopole Determinations From Multidirectionally Magnetized Lunar Crustal Anomaly Source Bodies","authors":"T. Chaffee,&nbsp;S. M. Tikoo,&nbsp;R. E. Maxwell,&nbsp;I. Garrick-Bethell","doi":"10.1029/2024JE008805","DOIUrl":"10.1029/2024JE008805","url":null,"abstract":"<p>Inversions of satellite observations of the lunar crustal magnetic field do not consistently produce regional magnetization directions consistent with a selenocentric axial dipolar field. We modeled the thermal evolution of anomaly source bodies in the lunar crust and found that large features (impact melt sheets and ejecta deposits) cool heterogeneously, but generally from the outside in. Regions within these bodies may remain above the Curie temperature of metallic iron long enough (10⁶ yrs) that uniform magnetization is unlikely if the lunar dynamo had Earthlike reversal frequency or other orientation changes. We modeled fields produced by non-uniformly magnetized source bodies. Alternate layers within these source bodies may cancel one another's field expression, reducing the satellite altitude field strength by a factor of up to 4 compared to a uniform magnetization. The surface field geometries of multidirectionally magnetized sources have complex features at the length scale of the subsurface magnetizations for each reversal. At 30 km satellite altitude, fields are smoothed and often resemble those of dipolar point sources. We found that Parker's method generally provides accurate magnetization directions for satellite altitude observations of anomalies that record near-antipodal reversals of a selenocentric dipole field. However, inaccurate paleofield directions may be retrieved if the paleofield exhibits non-antipodal dipole motion over time. Smaller lunar magnetic anomalies with high field intensities relative to the local background are the most likely to yield accurate magnetization directions; however, these anomalies are rapidly cooled and may not record the time-averaged behavior of the lunar dynamo.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008805","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144927381","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":"Subsurface Habitable Environments Revealed by Mud Volcanoes in Utopia Planitia on Mars and Implications for China's Tianwen-3 Mission","authors":"Le Wang,&nbsp;Jun Huang,&nbsp;Xiao Xiao,&nbsp;Long Xiao","doi":"10.1029/2025JE009075","DOIUrl":"10.1029/2025JE009075","url":null,"abstract":"<p>The Vastitas Borealis Formation (VBF) has been hypothesized to represent sedimentary remnants of ancient northern martian oceans. Widely distributed pitted cones across VBF are interpreted as most likely mud volcanoes, whose source regions might have hosted habitable environments. Assuming these features are mud volcanoes, we constrained the depths of previous potential mud reservoirs using a isostatic eruption model. The results show that the depths of mud reservoirs may have ranged from approximately 530 to 1,800 m, with maintained temperatures exceeding 20°C under high geothermal heat flux (45–60 mW/m²). Materials from these regions are of high priority for future sample return missions, for example Tianwen-3, the Mars sample return mission of China, aiming to search for martian biosignatures. Combing geological analysis and engineering constraints, we propose a scientifically very promising landing site in Utopia Planitia for Tianwen-3 mission.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144927382","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":"Shallow Multi-Layered Structures Within the Lunar Regolith Observed by the Chang’E-5 Radar","authors":"Jing Li,&nbsp;Rong Hu,&nbsp;Chunyu Ding,&nbsp;Hui Liu,&nbsp;Jianqing Feng,&nbsp;Sherif Hanafy","doi":"10.1029/2024JE008509","DOIUrl":"10.1029/2024JE008509","url":null,"abstract":"<p>Layered subsurface regolith structures and estimated regolith properties are crucial for revealing the evolutionary history of the Moon. We employed the Lunar Regolith Penetrating Radar (LRPR) onboard the Chang’E-5 (CE-5) probe, achieving high-resolution imaging of the shallow regolith. Through the full-waveform inversion (FWI) permittivity results of the LRPR data and the drilling pressure curve, we discovered multiple layers within 1.2 m beneath the lunar surface, and there are ejecta rock fragments in some areas. The multi-layered structure suggests they likely formed from ejecta deposition from small impact craters surrounding the landing site. Furthermore, we inferred that the evolutionary history of the impact craters in the landing area was approximately 70 million years (Ma) based on the thickness of the ejecta. The permittivity of the weathering layer correlates with the test results of lunar samples, confirming the reliability of our methodology. These findings provide crucial technical guidance for future lunar surface drilling and sample return missions.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144920613","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":"On the Crustal Architecture of the Terrestrial Planets","authors":"A. Broquet,&nbsp;J. Maia,&nbsp;M. A. Wieczorek","doi":"10.1029/2025JE009139","DOIUrl":"10.1029/2025JE009139","url":null,"abstract":"<p>Understanding the structure and composition of planetary crusts is fundamental for unraveling the diverse geologic pathways of rocky bodies in the solar system. In recent years, geophysical missions have shed light on the crustal architecture of the Moon and Mars. New missions are currently en route to Mercury and in preparation for Venus. Here, we provide an overview of our current knowledge of the crustal structure of the Moon, Mars, Mercury and Venus, and present nominal models for these planets. Planetary crusts are thought to have average thicknesses of ∼20 km (Venus), ∼30 km (Mercury, Moon) and higher (30–70 km, Mars), and generally represent a few percent of the silicate mass fraction of their planet. In comparison, crustal thickness on Earth is bimodal, with values of 40 and 7 km for the continental and oceanic crusts, respectively, for a global average of ∼19 km. We highlight that gravity inversions must account for the often-uneven resolution of gravity fields and show that the classical Bouguer anomaly filtering step can be avoided by simultaneously inverting for crustal density and thickness. Rather than discarding data, this method ascribes short-wavelength gravity anomalies to crustal density variations. For Mercury, Venus, and the Moon, we discuss the effect of having a laterally variable mantle density on crustal thickness inversions, and for Mars, we present an approach to consider a high-density basaltic crust. While crustal thickness inversions remain non-unique, we discuss that the distribution of tectonic and volcanic landforms can help constrain the range of plausible models.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JE009139","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144920614","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":"Enceladus Water Plume Modeling Using DSMC","authors":"A. Mahieux,&nbsp;D. B. Goldstein,&nbsp;P. L. Varghese,&nbsp;L. M. Trafton,&nbsp;G. Portyankina,&nbsp;L. W. Esposito,&nbsp;M. E. Perry,&nbsp;J. H. Waite,&nbsp;B. S. Southworth,&nbsp;S. Kempf","doi":"10.1029/2025JE009008","DOIUrl":"10.1029/2025JE009008","url":null,"abstract":"<p>This study investigates the water plumes of Saturn's moon, Enceladus, using Direct Simulation Monte Carlo (DSMC) modeling to analyze venting dynamics and plume structures. Building on prior research, we employ a parametrized DSMC approach to model water vapor and ice particle flows, leveraging Cassini spacecraft data from instruments such as the Ion and Neutral Mass Spectrometer and the Ultraviolet Imaging Spectrograph. The study explores whether vent conditions, such as mass flow rates, mixture temperatures, and particle sizes, can be inferred from observational data. We develop a computational framework to expand plume simulations beyond 10 km altitudes, incorporating gravitational and inertial forces in an Enceladus-fixed reference frame. A sensitivity analysis correlates vent parameters with observed data, identifying critical contributors such as vent orientation and location, mass flow rate, exit temperature, and ice grain characteristics. This approach reduces the dimensionality of fitting procedures, enabling robust parameter constraints and a more detailed understanding of plume dynamics. Key findings include constrained values for mass flow rates, ice grain radii assuming single-size particles, and exit temperatures (∼44–61 K), consistent with theoretical predictions. Additionally, variations in vent orientation and positional parameters were refined from the work of Porco et al. (2014, https://doi.org/10.1088/0004-6256/148/3/45). These results highlight the importance of collision dynamics in shaping plume structures. This work establishes a computationally efficient methodology for analyzing cryovolcanic plumes applicable to future missions exploring icy moons such as Enceladus or Europa. By prioritizing sensitive parameters, the study offers insights for optimizing observational strategies to maximize scientific yield.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JE009008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144915298","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 of the Thermal Conductivity of Dry and Icy Lunar Regolith Simulants","authors":"Henning Wache,&nbsp;Luca Kiewiet,&nbsp;Paul Zabel,&nbsp;Jürgen Blum","doi":"10.1029/2025JE009084","DOIUrl":"10.1029/2025JE009084","url":null,"abstract":"<p>This study investigates the thermal conductivity of lunar regolith simulants, both with and without the addition of ice. A novel icy regolith simulant was developed, combining microgranular water ice particles and lunar highlands simulant LHS-1. Thermal conductivity measurements were conducted in a thermal vacuum chamber over a temperature range of 100–450 K using the transient hot strip method. The results for dry regolith simulants align with the small magnitude and temperature dependence observed in Apollo samples. Icy simulants with low ice content (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&lt;</mo>\u0000 </mrow>\u0000 <annotation> ${&lt; } $</annotation>\u0000 </semantics></math>10 wt%) exhibited similarly low thermal conductivity at low temperatures, with minimal variation due to ice content. However, sublimation caused significant changes with increasing temperature, highlighting the influence of latent heat transport. Sublimation also induced cementation, suggesting that lunar ice deposits may have developed sintered outer layers. Interconnected icy regolith simulants displayed slightly higher thermal conductivity, even at low ice content. This work provides insights into the thermal properties of possible forms of icy and dry lunar regolith, particularly for ice-bearing regions near the lunar south pole. These findings support the development of thermophysical models and resource extraction experiments for permanently shadowed regions.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JE009084","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144915299","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":"Shock Melting and Melt Deposit Patterns in Oblique Impacts: Insights From Numerical Simulations","authors":"Xi-Zi Luo,&nbsp;Meng-Hua Zhu,&nbsp;Min Ding,&nbsp;Lukas Manske,&nbsp;Robert Luther,&nbsp;Kai Wünnemann","doi":"10.1029/2025JE009066","DOIUrl":"10.1029/2025JE009066","url":null,"abstract":"<p>Hypervelocity impacts induce shock melting and distribute melted materials across planetary surfaces. The impact angle significantly affects melt production and ejecta formation, but systematic studies of these processes in oblique impacts are limited. Here, we employ the shock physics code iSALE-3D to systematically simulate shock melting, crater excavation, ejection, and melt deposition under lunar gravity conditions with varying impact angles (10°–90°) and impactor diameters (1–30 km), producing transient craters with diameters ranging from ∼10 to 200 km. Simulation results show that the total melt volume decreases by ∼25% when the impact angle drops from 90<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ}$</annotation>\u0000 </semantics></math> (i.e., vertical impact) to 45<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ}$</annotation>\u0000 </semantics></math>, and by ∼85% when the angle reduces to 25<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ}$</annotation>\u0000 </semantics></math> (i.e., highly oblique impact). The ratio of ejected to generated melt generally remains constant for impact angles &gt;25<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ}$</annotation>\u0000 </semantics></math>, but increases significantly at lower impact angles. With more oblique impacts, melt deposits around craters gradually exhibit an uprange zone of avoidance, similar to the pattern of the entire ejecta blanket. Melt content within the ejecta generally increases with distance from the crater. For impact angles exceeding 45°, crossrange and downrange melt distributions closely resemble those generated by vertical impacts. Notably, our results demonstrate that impact angles &lt;45<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ}$</annotation>\u0000 </semantics></math> produce considerably reduced melt quantity and melt fraction in ejecta relative to vertical impacts, underscoring the critical role of considering impact angle when examining melt production in impact cratering.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144915313","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":"In Situ Observation of Weathering Rinds at the Zhurong Landing Site, Mars","authors":"Qing Zhang,&nbsp;John Carter,&nbsp;Mathieu Vincendon,&nbsp;François Poulet,&nbsp;Maxime Pineau,&nbsp;Lin Guo,&nbsp;Zhaopeng Chen,&nbsp;Dawei Liu,&nbsp;Bin Liu,&nbsp;Xin Ren,&nbsp;Jean-Pierre Bibring,&nbsp;Jianjun Liu,&nbsp;Chunlai Li","doi":"10.1029/2025JE009196","DOIUrl":"10.1029/2025JE009196","url":null,"abstract":"<p>The Zhurong rover conducted in situ spectral investigations of southern Utopia Planitia, where the bedrock composition remains relatively unknown due to dust cover. Here we identify some spectrally distinct dark patches sporadically occurring on rocks by combining the Multispectral Camera and Short-Wave Infrared data. These dark patches represent relatively dust-free surfaces and exhibit concave-up blue slopes in the near-infrared not identified in that area from orbital data. This spectral signature is most consistent with silica-enriched leached rinds on basaltic glass. The presence of such weathering rinds could imply leaching in an acidic aqueous environment of igneous rocks previously transported to the landing site as impact ejecta or pyroclastic deposits by explosive volcanism. In situ observations link the dark patches to the northern low-albedo regions, suggesting that the surficial acidic weathering may be more widespread and occurred in the northern lowlands under Amazonian climatic conditions.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144915311","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}