Journal of Geophysical Research: Planets最新文献

{"title":"High-Precision Imaging and TiO2 + FeO Content Estimation of Lunar Farside Subsurface Layers: Insights From Chang'e-4 Lunar Penetrating Radar Data","authors":"Huaqing Cao,&nbsp;Jing Li,&nbsp;Chang Zhang,&nbsp;Lige Bai","doi":"10.1029/2024JE008884","DOIUrl":"10.1029/2024JE008884","url":null,"abstract":"<p>The Chang'e-4 Lunar Penetrating Radar (LPR) has proven instrumental in uncovering the structure and composition of the Von Kármán crater on the lunar farside. Utilizing high-frequency (HF) LPR data collected during the first 53 lunar days, this study employs Least Squares Migration to achieve high-resolution imaging of shallow subsurface structures. Additionally, the peak frequency shift method is applied to estimate the loss tangent and the TiO₂ + FeO content of the shallow regolith. The average loss tangent of the shallow regolith ranges from 4.3 × 10⁻³ to 5.5 × 10⁻³, corresponding to an iron-titanium content of 11.2 wt% to 14.7 wt%. Along the Yutu-2 rover's traverse (300–500 m and 1,000–1,150 m), the regolith exhibits high TiO₂ + FeO content, suggesting that these materials may originate from deeper basalt layers. By integrating radar profiles with estimates of TiO₂ + FeO content, this study provides a detailed geological interpretation of subsurface layers and unique structures. These findings reconstruct critical geological events in the shallow subsurface at the landing site, offering new insights into the geological evolution of this region.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144910391","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":"Updated Estimates of the Sputtering Contributions to the Exosphere of Mercury From Magnetospheric Ion Precipitation","authors":"P. S. Szabo,&nbsp;A. R. Poppe,&nbsp;S. Fatemi,&nbsp;A. Mutzke,&nbsp;J. Huang,&nbsp;W. J. Sun,&nbsp;J. T. Zhao","doi":"10.1029/2025JE009058","DOIUrl":"10.1029/2025JE009058","url":null,"abstract":"<p>Ion impacts on airless bodies such as Mercury alter their surfaces and contribute to their exospheres via sputtering. Their exact contribution in comparison to other effects is still uncertain, but observations by the MESSENGER spacecraft largely indicated influences from micrometeoroids. In this paper, we present an updated modeling of sputtering at Mercury to help estimate the role of sputtering at average solar wind conditions. To achieve this, we account for ion precipitation due to the planet's magnetosphere and for the presence of a porous regolith: We combine H⁺ and He⁺⁺ fluxes to the surface from the Amitis hybrid model with sputter yields derived from a regolith simulation in SDTrimSP-3D. We find that H⁺ and He⁺⁺ show similar precipitation patterns, but H⁺ energies are much more reduced and variable than those of He⁺⁺. Globally, H⁺ and He⁺⁺ contribute about equal amounts of sputtering. Our laboratory-calibrated sputter yields are significantly lower than estimates used in previous studies, resulting in a global sputtering source of around 10²³ atoms s⁻¹. Specifically for Ca and Mg exospheres we find source rates from sputtering that are largely unaffected by Mercury's seasonal orientation and too small by up to around two orders of magnitudes to explain MESSENGER observations. This supports a micrometeoroid-impact-dominated source of refractory elements. We find, however, that this is an effect of the reduced magnetospheric precipitation at Mercury. At other bodies such as the Moon, a different regime should be prevalent and sputtering should contribute at least similarly to the exospheres of refractory elements.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144910390","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":"Discovery of Coesite on the Lunar Farside","authors":"Zhan Zhou,&nbsp;Sen Hu,&nbsp;Huicun He,&nbsp;Yubing Gao,&nbsp;Linxi Li,&nbsp;Liang Gao,&nbsp;Mengfan Qiu,&nbsp;Disheng Zhou,&nbsp;Huanxin Liu,&nbsp;Zhihu Ye,&nbsp;Xu Tang,&nbsp;Lixin Gu,&nbsp;Xiaoguang Li,&nbsp;Wei Yang,&nbsp;Yangting Lin,&nbsp;Xian-Hua Li,&nbsp;Fu-Yuan Wu","doi":"10.1029/2025JE009052","DOIUrl":"10.1029/2025JE009052","url":null,"abstract":"<p>The Moon has been highly shocked as evidenced by numerous impact craters on its surface. High-pressure minerals are expected to form during these shock events and can be used to unravel the pressure and temperature conditions for the shock events. However, high-pressure minerals are rarely reported in the lunar returned samples, yielding a discrepancy with the prediction. The lunar soils returned by the Chang'e-6 (CE6) mission from the South Pole-Aitken (SPA) basin provide new opportunities to investigate the shock metamorphism of the lunar samples and the shock events on the Moon. Here, we reported the discovery of coesite in a shock-induced melt pocket from a CE6 mare basalt, which could have experienced a shock event with a peak pressure of ∼24 GPa. The coesite exhibits two types of occurrences, a polycrystalline aggregate in the center and a ring along the margin of a silica clast. The coesite could have been formed by solid-state transformation followed by partial conversion to silica glass during decompression. The coesite has a higher survival temperature and a slower back-transformation rate than most other high-pressure minerals, which are favorable for its preservation under high-temperature conditions of lunar soils induced by impacts. These findings provide new insights for the preservation of coesite in natural shock events and indicate that more thermal-resistant high-pressure minerals could have been formed and preserved in lunar samples than previously thought, providing new targets for studying the shock events on the Moon.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144910468","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":"Investigations of the Sinus Aestuum DMD: An Anomalously Large and Compositionally Distinct Lunar Pyroclastic Deposit","authors":"Cosmo T. Sikes,&nbsp;Jessica M. Sunshine,&nbsp;Megan E. Newcombe","doi":"10.1029/2024JE008919","DOIUrl":"10.1029/2024JE008919","url":null,"abstract":"<p>The Sinus Aestuum (SA) dark mantle deposit (DMD) is a regional pyroclastic deposit on the central lunar near-side. Spectra from the SA DMD are anomalous when compared to other DMDs and have been interpreted to represent a high abundance of the mineral spinel. The SA spinels are compositionally distinct compared to other lunar spinels and their pyroclastic association suggests that a unique volcanic process has occurred. Spectral mixture analysis is used to map the distribution of the spinel-bearing pyroclastics (SBPs) across the region. The extent of SBPs reveals that the SA DMD is much larger than previously thought (∼221,000 km²) and is distributed over an approximately circular region, consistent with a large eruption from a single, central source. However, variable abundances of SBPs are observed on smaller scales, suggesting a more complicated history. The distribution of these SBPs, including a portion of non-spinel bearing DMD discovered by this study within the SA region, is analyzed across a variety of spatial scales to infer what processes may have produced the observed variability. There is evidence of small-scale volcanism in addition to the larger eruption forming the broader DMD. An ultraviolet absorption, which is absent in other regional DMDs, is discovered in the spectra of SA SBPs, which may indicate the presence of Ti-bearing oxides. It is unclear whether the spinel itself has caused this feature, or if it is the result of a co-occurrence of ilmenite within the SBPs.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008919","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144910467","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 Subsurface Structure of the Martian Utopia Basin Revealed by the Radar Data of the Zhurong Rover","authors":"Huitang Li,&nbsp;Qinghong Sheng,&nbsp;Bo Wang,&nbsp;Jun Li,&nbsp;Xiao Ling","doi":"10.1029/2024JE008819","DOIUrl":"10.1029/2024JE008819","url":null,"abstract":"<p>The Zhurong rover, a key component of China's inaugural Mars exploration mission, successfully landed on the southern Utopia Planitia on 15 May 2021. Equipped with a dual-channel ground-penetrating radar (GPR), the rover conducted comprehensive investigations of the martian subsurface. This study focuses on the processing of GPR data collected between 25 May and 31 October 2021, utilizing both high and low-frequency channels. By integrating GPR data with images from the High-Resolution Imaging Camera and the Navigation and Terrain Cameras, this research offers valuable insights into the subsurface structure of the landing site. The low-frequency data indicate a multi-layered underground structure extending to a depth of 80 m. The strata display a progressive increase in roughness from top to bottom, likely resulting from a combination of sedimentary processes, including flood deposition, long-term weathering, and repeated meteorite impacts. These processes imply a history of intermittent flooding events, gradual sediment accumulation, and the effects of prolonged weathering and impacts, likely driven by climatic and environmental fluctuations. Meanwhile, the high-frequency data have revealed the reshaping of martian surface sediments caused by meteorite impacts and weathering in the regolith up to a depth of 5 m underground. These findings are crucial for understanding the geological evolution of Utopia Planitia.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144910469","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":"Lobate Forms Around Craters on the Moon and Mercury: Origin From Landslides, Ejecta Flows and Modification Stage Collapse","authors":"A. J. Blance,&nbsp;A. R. Lennox,&nbsp;D. A. Rothery,&nbsp;M. Balme,&nbsp;J. Wright,&nbsp;V. Galluzzi,&nbsp;S. J. Conway","doi":"10.1029/2025JE008980","DOIUrl":"10.1029/2025JE008980","url":null,"abstract":"<p>Lobate forms emanate from impact craters and have morphologies indicating ground-hugging emplacement via flow. We present global surveys of lobate forms on the Moon and Mercury. Very few examples have previously been reported on either body, with debate over their interpretation as either crater rim landslides or ejecta flows. We identify 92 lobate forms on the Moon, and 98 on Mercury, a significant increase on previously reported examples. 98% extend downslope into an adjacent or overlapped antecedent crater. Lobate forms are directly linked to impact cratering processes: evidence for syn-impact formation, including impact melt on top of lobate forms, suggests ∼71% formed due to exterior collapse of source crater material into antecedent craters during source crater modification. 24% of examples instead appear to be landslides on antecedent crater rims, triggered by the newer impact. Understanding the formation of these features therefore provides new insight into impact cratering and mass movements processes. Equivalent lobe mobilities and occurrence rates on the volatile-depleted Moon and the somewhat volatile-enriched Mercury suggest volatiles are not necessary for formation. However, lobate form mobilities on the Moon and Mercury are lower than for comparable martian features, thought to require ground-ice to form, potentially supporting the idea that very high volatile content enables more mobile mass movements. Two lobate forms on flat ground (Hokusai and Piazzolla craters, Mercury) are morphologically similar to martian layered ejecta, possibly indicating a more significant influence of volatiles for these examples or a more enigmatic formation process.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JE008980","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144910466","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":"Reliable Paleomagnetic Records From Single-Vortex Iron Particles","authors":"Shichu Chen,&nbsp;Thomas A. Berndt,&nbsp;Wyn Williams,&nbsp;José A. P. M. Devienne,&nbsp;Lesleis Nagy,&nbsp;Peihong Wu","doi":"10.1029/2025JE009167","DOIUrl":"10.1029/2025JE009167","url":null,"abstract":"<p>Dusty olivine containing Fe-rich kamacite grains in chondrules can faithfully record the early solar magnetic fields. To retrieve paleointensity estimates, most experimental protocols are based on the dominance of uniformly magnetized single-domain (SD) particles. However, direct observation shows that most particles adopt a non-uniform magnetic structure. This inconsistency potentially represents a major impediment in reliably reconstructing ancient magnetic fields. Here we present a micromagnetic based model, the State Group Algorithm, that enables efficient simulations of thermoremanence acquisition in magnetic particles with single-vortex (SV) domain states. Our results show that these particles can acquire a thermoremanence that is linear proportional to the external field up to <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 <mn>100</mn>\u0000 <mspace></mspace>\u0000 <mtext>μT</mtext>\u0000 </mrow>\u0000 <annotation> ${sim} 100,{mutext{T}}$</annotation>\u0000 </semantics></math>. They also have cooling rate effects that are generally weaker than those of SD particles. Notably, a small subset of SV particles can exhibit negative cooling rate effects, leading to underestimates in paleointensity. We conclude that SV particles are reliable paleomagnetic recorders.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144897820","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":"New Geophysical Constraints for Intrusive Magmatism at Large Martian Volcanoes: Implications for Crustal Thickness and Volatile Outgassing","authors":"N. L. Wagner,&nbsp;P. B. James","doi":"10.1029/2025JE008959","DOIUrl":"10.1029/2025JE008959","url":null,"abstract":"<p>Volcanic materials exert both downward and upward forces on a planet's lithosphere, depending on where they are emplaced. On Mars, numerous studies have used gravity and topography data to ascertain the contribution of each of these styles of emplacement to measured fields. We use a novel methodology that allows for the thickness of an intrusive body to vary to more thoroughly model how intrusive magma flexes the lithosphere and use this to estimate the relative proportion of intrusive to extrusive materials under major Martian volcanoes. We find proportions that imply larger volumes of intrusive material compared to erupted, which is more in line with non-geophysical methods. Our results additionally imply a significant volume of outgassed volatiles into the atmosphere relatively later in Martian history which has implications for the thickness and composition of the ancient Martian atmosphere.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JE008959","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144894412","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":"Scales of Martian Crustal Magnetization Constrained by MAVEN, InSight, and Zhurong","authors":"O. M. Romeo,&nbsp;M. Manga,&nbsp;R. J. Lillis,&nbsp;A. Mittelholz","doi":"10.1029/2025JE008986","DOIUrl":"10.1029/2025JE008986","url":null,"abstract":"<p>While Mars does not possess a currently active geodynamo, remanent crustal magnetization has been found across the planet and contains records of the origin, scale, and timing of Martian magnetization. The first in situ measurements of the Martian magnetic field on the planet's surface, at the InSight and Zhurong landing sites, allow for better constraints on magnetization coherence and depth scales near the surface, as crustal fields are closely related to a variety of geological and topographic features. We develop Monte Carlo models of the Martian crustal magnetization near the two landing sites on small-scales (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&lt;</mo>\u0000 </mrow>\u0000 <annotation> ${&lt; } $</annotation>\u0000 </semantics></math>50 km) to meso-scales (100<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 </mrow>\u0000 <annotation> ${-}$</annotation>\u0000 </semantics></math>1,000 km) to compute altitude profiles of the magnetic field intensity. We compare our simulations with the Langlais et al. (2019, https://doi.org/10.1029/2018je005854) crustal field model and surface measurements, indicating that power law distributions more accurately describe Martian altitude profiles compared to Gaussian models. Observations are best explained by fractal parameter <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>β</mi>\u0000 </mrow>\u0000 <annotation> $beta $</annotation>\u0000 </semantics></math> values near 2.7 and coherence scales roughly 250 km near InSight, with larger coherence scales and possibly thicker crustal magnetization near Zhurong. Motivated by these length scales, we create additional magnetization models based on the geological units near each lander to relate them to different time periods of Martian history. Our results suggest at least one polar field reversal in Martian history based on the simulated magnetization near the North-South dichotomy boundary. Furthermore, we propose that the Martian geodynamo might have weakened or suspended during the late Noachian, followed by revitalization of the core dynamo during the Hesperian period.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JE008986","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144892483","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":"An ANGSA Study: Crystal Size Distributions of Ilmenite in Basalts From Apollo 17 Drive Tube 73002","authors":"Jessika L. Valenciano,&nbsp;Clive R. Neal,&nbsp;Scott A. Eckley,&nbsp;Charles K. Shearer,&nbsp;the ANGSA Science Team","doi":"10.1029/2024JE008580","DOIUrl":"10.1029/2024JE008580","url":null,"abstract":"<p>Double drive tubes 73002 (upper) and 73001 (lower) were collected during Apollo 17 from a landslide deposit at the base of the South Massif in the Taurus-Littrow valley. The drive tubes were opened for the first time as part of the Apollo Next Generation Sample Analysis (ANGSA) project, representing “new” samples from the Moon. Many lithic fragments (&gt;1 mm in size) were extracted from the core during core dissection and preliminary examination (PE), including high-Ti mare basalt clasts. Those &gt;4 mm fragments were three-dimensionally imaged using X-ray computed tomography (XCT). The crystal size distributions of ilmenite were measured in 10 high-Ti mare basalts and within the matrix of an impact melt breccia from drive tube 73002 using thin section “slices” from the 3D XCT scans. Residence times (of the crystals in the melt from which they grew) were estimated using experimental growth rates for each sample with all but 73002,2015 being relatively short (&lt;1 year). Linear (constant) cooling rates were determined, expanding upon data already obtained from other Apollo 17 high-Ti basalts showing that these ANGSA basalt clasts had similar cooling histories to those previously studied. Comparison with ilmenite cooling rate experiments estimated cooling rates of &lt;10°C/h for each clast.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008580","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144888315","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}