Journal of Geophysical Research: Planets最新文献

{"title":"Modeling Lake Bonneville Paleoshoreline Erosion at Mars-Like Rates and Durations: Implications for the Preservation of Erosional Martian Shorelines and Viability as Evidence for a Martian Ocean","authors":"Zachary J. Baran,&nbsp;Benjamin T. Cardenas","doi":"10.1029/2024JE008851","DOIUrl":"https://doi.org/10.1029/2024JE008851","url":null,"abstract":"<p>Mars may have had an ancient ocean filling its northern lowlands until around 3.5 billion years ago. The existence or lack of such a large body of water would have important implications on the ancient martian climate, landscapes, and habitability. One proposed piece of evidence is preserved paleoshorelines on the martian surface along the dichotomy boundary. Paleoshorelines on Earth are often recognized as subtle breaks in slopes that are laterally persistent and at consistent elevations. Is it probable, or even possible, that paleoshoreline topography on Mars might persist for 3.5 billion years, even at the slow erosion rates estimated for the martian surface? Here, we use topographic data showing well-preserved Earth-analog erosional paleoshorelines from Lake Bonneville in modern day Utah and numerically model their erosion at Mars-like rates for 3.5 billion years. Depending on the chosen diffusivity value and scale of the terrain used in each experiment, identifiable paleoshoreline features may or may not persist after the modeled erosion; higher diffusivities and smaller scales favor paleoshoreline erosion and smaller diffusivities and larger scales favoring paleoshoreline preservation.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008851","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143787059","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":"Impacts Into Titan's Methane-Clathrate Crust as a Source of Atmospheric Methane","authors":"S. Wakita,&nbsp;B. C. Johnson,&nbsp;J. M. Soderblom,&nbsp;J. K. Steckloff,&nbsp;A. V. Johnson,&nbsp;C. D. Neish,&nbsp;J. Shah,&nbsp;P. Corlies","doi":"10.1029/2024JE008624","DOIUrl":"https://doi.org/10.1029/2024JE008624","url":null,"abstract":"<p>Titan is the only icy satellite in the solar system with a dense atmosphere. This atmosphere is composed primarily of nitrogen with a few percent methane, which supports an active, methane-based hydrological cycle on Titan. The presence of methane, however, is intriguing, as its lifetime is likely much shorter than the age of the solar system due to its irreversible destruction by UV photolysis. To explain Titan's current atmospheric methane abundance, it is hypothesized that a replenishment mechanism is needed. One such mechanism may be crater forming impacts; a methane-clathrate layer potentially covering the surface of Titan may act as a reservoir that releases methane when disrupted by impacts. Here, we perform impact simulations into methane-clathrate layers to investigate the amount of methane released via impacts. Our simulations show that the amount of methane released into the atmosphere depends on both the impactor size and the methane-clathrate layer thickness. A single 20-km-diameter impactor releases up to 1% of Titan's current atmospheric methane mass; the effect of impact obliquity and surface porosity may further increase the released mass by a factor of 2–3. The release rate from impacts is lower than the net loss rate by photolysis, but the released methane mass via impacts can enhance the lifetime of methane in Titan's atmosphere by up to 3%. Menrva-sized (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&gt;</mo>\u0000 </mrow>\u0000 <annotation> ${ &gt;} $</annotation>\u0000 </semantics></math>400 km diameter) crater-forming impacts directly liberate <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>15% of Titan's current atmospheric methane. The direct heating of the atmosphere by the impactor might contribute to additional crustal heating and methane release.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008624","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143793674","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":"Gravity and Magnetic Field Signatures in Hydrothermally Affected Regions on Mars","authors":"Anna Mittelholz,&nbsp;Max Moorkamp,&nbsp;Adrien Broquet,&nbsp;Lujendra Ojha","doi":"10.1029/2024JE008832","DOIUrl":"https://doi.org/10.1029/2024JE008832","url":null,"abstract":"<p>Multiple lines of evidence indicate that liquid water-rock interactions occurred on ancient Mars, particularly within the crust, where hydrothermal systems have been hypothesized. Such hydrothermal circulation (HC) can significantly lower temperatures in the crust, thereby restricting the viscoelastic relaxation of impact craters. Craters with minimal relaxation are characterized by their large depth-to-diameter ratio and prominent Bouguer gravity anomalies. Additionally, HC can induce magnetic anomalies through chemical remanent magnetization (CRM). Consequently, if HC was widespread on Mars, the gravitational signatures of unrelaxed craters may correlate with their magnetic signatures. To investigate how HC influenced the magnetic characteristics of the Martian crust, we focus on the region surrounding several unrelaxed craters in the southern highlands, where hydrothermal activity was likely prevalent. We use a newly developed joint inversion approach and model magnetization and density in such regions to investigate how hydrothermal systems affect those parameters. The inversion approach makes use of a mutual information term in which models with a parameter relationship are favored, that is, models in which magnetization and density distributions are correlated. Despite showing large Bouguer gravity anomalies and forming over 3.75 billion years ago, when the Martian dynamo was most likely active, investigated craters and surrounding regions exhibit minimal magnetic anomalies. We propose that this lack of magnetic signatures is most likely due to demagnetization of the crust through CRM, induced by HC long after the Martian dynamo ceased. Our findings suggest that deep, long-lived hydrothermal systems—likely fueled by heat-producing elements—were present, potentially creating habitable conditions on early Mars.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008832","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143793672","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":"Can the Moon's Center of Mass–Center of Figure Offset Be Explained With a Uniform Primordial Crust?","authors":"Matt J. Jones,&nbsp;Fiona Nichols-Fleming,&nbsp;Alexander J. Evans,&nbsp;Brandon C. Johnson,&nbsp;Jeffrey C. Andrews-Hanna","doi":"10.1029/2024JE008783","DOIUrl":"https://doi.org/10.1029/2024JE008783","url":null,"abstract":"<p>A fundamental constraint on the Moon's interior mass distribution is the 1.935-km lunar center of mass (COM)–center of figure (COF) offset. Extant constraints on the mass asymmetry that generates the COM-COF offset—commonly attributed to a crustal thickness asymmetry wherein the nearside crust is thinner than that of the farside—do not permit a unique solution for the lunar interior structure. Using simple analytical models of isostasy and porosity evolution, we quantify potential contributions to the lunar mass asymmetry from nearside-farside asymmetries (specifically, spherical harmonic degree-1 variations) in porosity, crustal basalts, and dense late-stage magma ocean cumulates. We demonstrate that these asymmetries could simultaneously explain the COM-COF offset and allow for a lunar crust that formed with globally uniform thickness and porosity. Scenarios with an excess of ∼10–44 km of late-stage cumulates in the nearside relative to the farside allow for full ranges of 5%–12% nearside anorthosite porosity, 1–2 km of excess nearside basalts, and nearside crustal thickness of either 30 km or 38 km. Furthermore, under specific conditions (30-km nearside crust with low porosity and high late-stage cumulate density of ∼3,600 kg/m³), the COM-COF offset permits an initially uniform crust as well as a present-day crust with uniform thickness. While observational constraints do not favor perfectly symmetric present-day crustal thickness, our analyses highlight the importance of higher fidelity characterization of the lunar interior structure and the use of caution in investigations that fundamentally rely on lunar crustal thickness constraints.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143787294","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":"Gallium and Germanium Concentrations From the MER Alpha Particle X-Ray Spectrometers: Evidence of Global Trace Element Enrichment","authors":"A. L. Knight,&nbsp;S. J. VanBommel,&nbsp;R. Gellert,&nbsp;J. A. Berger,&nbsp;J. G. Catalano,&nbsp;J. Gross,&nbsp;J. R. Christian","doi":"10.1029/2024JE008569","DOIUrl":"https://doi.org/10.1029/2024JE008569","url":null,"abstract":"<p>The Mars Exploration Rovers (MER) <i>Spirit</i> and <i>Opportunity</i>, sent to Gusev crater and Meridiani Planum, respectively, determined the chemical composition of martian materials with their Alpha Particle X-ray Spectrometers (APXS). The MER APXS was effective at routinely quantifying major, minor, and select (Ni, Zn, Br) trace elements at levels down to ∼50 ppm but often reached detection limits for other trace elements (e.g., Ga and Ge during typical individual analyses of a single sample). To enable precise quantification of additional trace elements, a database of MER APXS target properties (e.g., location, feature, target, formation, target type, sample preparation) was created, enabling the construction of a library of composite (i.e., summed) spectra with improved statistics. Composite spectra generated from individual spectra with shared characteristics have a higher potential for resolving and thus quantifying trace element peaks. Analyses of composite spectra from Meridiani Planum and Gusev crater indicate that the molar Ga to Al ratio is relatively constant throughout both regions and is in line with predicted values for the martian crust and measured values in martian meteorites. Gallium and aluminum likely do not volatilize and instead remain together during volcanism and aqueous alteration. In contrast, Ge is enriched at least an order of magnitude relative to martian meteorites, and the molar Ge to Si ratio is much more variable across Meridiani Planum and Gusev crater. Enrichment of Ge may be a global phenomenon resulting from volcanic outgassing of volatiles and subsequent overprinting by local mobilization and enrichment via hydrothermal fluids.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143778333","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":"Magma Chamber Longevity on Mars and Its Controls on Crustal Structure and Composition","authors":"Arka Pratim Chatterjee,&nbsp;Christian Huber,&nbsp;James W. Head III,&nbsp;Olivier Bachmann","doi":"10.1029/2024JE008798","DOIUrl":"https://doi.org/10.1029/2024JE008798","url":null,"abstract":"<p>In volcanically active planetary bodies, the depths and longevity of crustal magma storage critically control eruptibility and crustal composition. A paucity of relevant observations and models has challenged our understanding of the development of crustal magma storage systems on Mars and their role in the apparent lack of evolved compositions. Here, we use numerical modeling, together with recent results from the InSight mission, to study the evolution of crustal magma chambers on Mars and conditions that promote their growth and eruptibility. We find that the martian crust can be divided, by depth, into three major domains. For Elysium Planitia (the InSight landing site), at depths ≤15 km (∼1.5 kbar), trapped magma pods are small, short-lived, with high diking potential, hindering the production of evolved compositions. While depths &gt;25 km (∼2.5 kbar) can host long-lived magma chambers, 15–25 km (∼2 ± 0.5 kbar) marks a transition where magma chambers could grow while concurrently expelling magma. Interestingly, this narrow depth window overlaps with the depth of an intra-crustal discontinuity reported by InSight, suggesting a possible magmatic origin for the discontinuity. We further show that the crustal thermal gradient strongly controls this transition depth, indicating the possible variability of the domain depths in different terrains. Our results also support the likelihood of deep-seated magmatism beneath the seismically active Cerberus Fossae, suggesting that magmatism continues to play a major role in shaping the martian crust.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749397","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":"Fractional Crystallization Scenario for Magma Evolution on Mercury Inferred From Geochemical Variation Around the Caloris Basin","authors":"K. Hirata,&nbsp;T. Usui,&nbsp;E. Caminiti,&nbsp;J. Wright,&nbsp;S. Besse","doi":"10.1029/2024JE008788","DOIUrl":"https://doi.org/10.1029/2024JE008788","url":null,"abstract":"<p>The observed geochemical heterogeneity on the surface of Mercury is key to understanding the planet's volcanic activity and mantle conditions. The Caloris basin shows a diversity in elemental composition, spectral properties, and geomorphology, both within and around it. However, the relationship among these characteristics has not been well understood due to the mismatch in spatial resolutions of the available observation data. This study investigates the geochemical end-members around the Caloris basin, overcoming the limitation of the low spatial resolution of MESSENGER's X-Ray Spectrometer (XRS) data. End-member units are defined using spectral and geomorphological units from MESSENGER's VIS-NIR spectral data and high-resolution images, with the assumption of homogeneous elemental compositions within each unit. A mixing model is constructed to reproduce the XRS data by mixing the end-members, and we solve the inverse problem to calculate the respective end-member compositions. Five end-member compositions were determined, including those corresponding to the post-Caloris volcanic smooth plains interior and exterior to the basin and surrounding pre-Caloris crust. Two smooth plains units, which are geomorphologically indistinguishable but spectrally distinct, showed a compositional variation consistent with magma evolution through fractional crystallization. This suggests that they originated from parent magmas with a common composition. The pre-Caloris crust units showed a large compositional variation, ranging from low- to high-Mg content, implying the potential existence of high-Mg crusts comparable to the HMR. The observed crustal diversity could be explained by relatively minor heterogeneity in source mantle compositions and/or conditions of partial melting within the mantle.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008788","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143749398","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":"(16) Psyche's Different Possible Formation Scenarios and Internal Structures From Current Constraints","authors":"Carver J. Bierson,&nbsp;Samuel W. Courville,&nbsp;Anton Ermakov,&nbsp;Linda T. Elkins-Tanton,&nbsp;Mark Wieczorek,&nbsp;Ryan S. Park,&nbsp;Namya Baijal","doi":"10.1029/2024JE008640","DOIUrl":"https://doi.org/10.1029/2024JE008640","url":null,"abstract":"<p>One of the central questions to be addressed by the NASA Psyche mission is the composition and origin of the asteroid (16) Psyche. In preparation of the mission's planned arrival in 2029, in this work we explore how different internal structures may be expressed on (16) Psyche. We model the core size and shape that may exist at (16) Psyche given currently available constraints. We find that if Psyche has compositional layering, then tectonic features accommodating large amounts of compression from pore closure and a freezing core may be present. We also find that because of (16) Psyche's elongated shape and fast rotation, it is important to properly reference the elevations to the geoid (i.e., the accelerations a particle will feel) when interpreting possible mass wasting effects.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143741546","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":"Gravity and Radio Science Investigation at the Moons of Uranus to Reveal Subsurface Oceans and Characterize Interior Structures","authors":"Flavio Petricca,&nbsp;Damon Landau,&nbsp;Mohit Melwani Daswani,&nbsp;Julie Castillo-Rogez","doi":"10.1029/2024JE008715","DOIUrl":"https://doi.org/10.1029/2024JE008715","url":null,"abstract":"<p>The prospect that the five major moons of Uranus could host subsurface oceans makes them high-priority targets for future exploration. Different techniques can be used to search for deep oceans in these objects. Here, we focus on ocean detection and characterization from measurements of the moons' response to the gravitational tides and librations generated by Uranus forcing. We simulate the gravity and radio science investigations of a future mission by assuming different realistic trajectories and payload specifics of the anticipated Uranus Orbiter and Probe. A key finding is that observations of Umbriel's tidal response can provide robust evidence of the existence of a subsurface ocean at that moon. For all the moons except Oberon, measurements of the forced librations can also provide evidence of the existence of the oceans. Because of the challenges associated with detecting cold oceans through magnetic induction, gravity and radio science will provide powerful tools to understand whether oceans were preserved from freezing throughout the evolution of the moons.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008715","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143717094","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":"Simulating Impacts of Electron Precipitation on Mars' Nightside Ionosphere With an Empirical Model","authors":"M. Marquette,&nbsp;R. J. Lillis,&nbsp;D. J. Pawlowski,&nbsp;J.-Y. Chaufray,&nbsp;Y. J. Ma,&nbsp;F. González-Galindo,&nbsp;D. L. Mitchell,&nbsp;J. S. Halekas,&nbsp;M. Benna,&nbsp;M. K. Elrod,&nbsp;J. R. Espley,&nbsp;J. R. Gruesbeck,&nbsp;S. M. Curry","doi":"10.1029/2025JE008953","DOIUrl":"https://doi.org/10.1029/2025JE008953","url":null,"abstract":"<p>With the aim of improving global simulations of the Martian ionosphere, we present an empirical model of 137 electron impact processes—including ionization, dissociation, and excitation—on the nightside of Mars, based on MAVEN in situ data collected between 2014 and 2019. The empirical model demonstrates the significant impact magnetic field conditions have on nightside ionization rates, with different magnetic topologies reversing trends previously seen in ionization dependence on magnetic field strength: closed field lines on the nightside show a decrease in ionization with stronger fields, while topologies where field lines connect to a source of plasma at one or both ends show an increase of ionization with stronger fields. This empirical model is coupled with magnetic fields from MHD simulations of the Martian magnetosphere, as input to the PCM-Mars and M-GITM thermosphere-ionosphere models, to provide a source of ionization on the nightside. Finally, we present new simulations of the global ionosphere with ionization sources on both the dayside and, for the first time, the nightside.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143717389","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}