Journal of Geophysical Research: Planets最新文献

{"title":"Alkali Trace Elements Observed by MarSCoDe LIBS at Zhurong Landing Site on Mars: Quantitative Analysis and Its Geological Implications","authors":"Yuxuan Luo,&nbsp;Jianjun Liu,&nbsp;Zhaopeng Chen,&nbsp;Yizhong Zhang,&nbsp;Xing Wang,&nbsp;Xin Ren,&nbsp;Xiangfeng Liu,&nbsp;Zhenqiang Zhang,&nbsp;Weiming Xu,&nbsp;Rong Shu","doi":"10.1029/2024JE008366","DOIUrl":"10.1029/2024JE008366","url":null,"abstract":"<p>Mars Surface Composition Detector (MarSCoDe) is one of the important payloads carried by the Zhurong rover, China's first Mars exploration mission Tianwen-1. The laser-induced breakdown spectroscopy (LIBS) instrument of MarSCoDe is mainly used to detect major and trace elements on the surface of Mars. The quantitative analysis of alkali trace elements, namely lithium (Li), strontium (Sr), and rubidium (Rb), holds significance in unraveling the geological evolution of the Zhurong landing site. This study focuses on establishing univariate calibration models using MarSCoDe LIBS spectra from 84 samples tested in the ground laboratory. The accuracy of these models, within a few parts per million (ppm), was subsequently validated through the analysis of 12 onboard MarSCoDe Calibration Targets (MCCTs). With these models, Li, Sr, and Rb concentrations in the surface targets during the initial 300 sols (Martian days) traverse were determined. These concentrations ranged from 6 to 18, 106–628, and 22–87 ppm, respectively. Our results suggest that Li, Sr, and Rb are mainly related to the igneous rock components in the rocks and soils at the Zhurong landing site. The major secondary minerals in MarSCoDe scientific targets are likely small amounts of sulfates, which appear to have formed from the acidic weathering of recent surface brine. Clay minerals are likely either absent or very sparse in the scientific targets. The surface igneous materials at the landing site likely have originated from the most recent lava flow during the Amazonian epoch.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141851727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Geochemical and Mineralogical Signature of Glaciovolcanism Near Þórisjökull, Iceland, and Its Implications for Glaciovolcanism on Mars","authors":"Candice C. Bedford,&nbsp;Elizabeth B. Rampe,&nbsp;Michael T. Thorpe,&nbsp;Ryan C. Ewing,&nbsp;Kashauna Mason,&nbsp;Briony Horgan,&nbsp;Amanda Rudolph,&nbsp;Mathieu G. A. Lapôtre,&nbsp;Prakhar Sinha,&nbsp;Marion Nachon,&nbsp;Emily Champion,&nbsp;Lauren Berger,&nbsp;Ewan Reid,&nbsp;Patrick C. Gray","doi":"10.1029/2023JE008261","DOIUrl":"10.1029/2023JE008261","url":null,"abstract":"<p>Candidate glaciovolcanic landforms have been identified across Mars, suggesting that volcano-ice interactions may have been relatively widespread in areas that once contained extensive surface and near-surface ice deposits. To better constrain the detection of glaciovolcanism in Mars' geological record, this study has investigated and characterized the petrology, geochemistry, and mineralogy of three intraglacial volcanoes and an interglacial volcano in the Þórisjökull area of southwest Iceland. Our results show that glaciovolcanism creates abundant, variably altered hyaloclastite and hyalotuff that is sufficiently geochemically and mineralogically distinctive from subaerially erupted lava for identification using instruments available on Mars rovers and landers. Due to the lower gravity and atmospheric pressure at the surface of Mars, hyaloclastite and hyalotuff are also more likely to form in greater abundance in Martian glaciovolcanoes. Our results support that magmatism following deglaciation likely triggers decompression melting of the shallow mantle beneath Iceland, creating systematic changes in geochemistry and mineralogy. Glaciation can also suppress magmatism at its peak, encouraging the formation of shallow fractionated magma chambers. As such, it is possible for the crustal loading of an ice cap to enhance igneous diversity on a planet without plate tectonism, creating glass-rich, altered, and mineralogically diverse deposits such as those discovered in Gale crater by the Curiosity rover. However, as the eroded products of glaciovolcanism are similar to those formed through hydrovolcanism, the presence of a glaciovolcanic landform at the source is required to confirm whether volcano-ice interactions occurred at the sediment source.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JE008261","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141849637","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":"Three-Dimensional Venus Cloud Structure Simulated by a General Circulation Model","authors":"Wencheng D. Shao,&nbsp;João M. Mendonça,&nbsp;Longkang Dai","doi":"10.1029/2023JE008088","DOIUrl":"10.1029/2023JE008088","url":null,"abstract":"<p>The clouds have a great impact on Venus's energy budget and climate evolution, but its three-dimensional structure is still not well understood. Here we incorporate a simple Venus cloud physics scheme into a flexible GCM to investigate the three-dimensional cloud spatial variability. Our simulations show good agreement with observations in terms of the vertical profiles of clouds and H₂SO₄ vapor. H₂O vapor is overestimated above the clouds due to efficient transport in the cloud region. The cloud top decreases as latitude increases, qualitatively consistent with Venus Express observations. The underlying mechanism is the combination of H₂SO₄ chemical production and meridional circulation. The mixing ratios of H₂SO₄ at 50–60 km and H₂O vapors in the main cloud deck basically exhibit maxima around the equator, due to the effect of temperature's control on the saturation vapor mixing ratios of the two species. The cloud mass distribution is subject to both H₂SO₄ chemical production and dynamical transport and shows a pattern that peaks around the equator in the upper cloud while peaks at mid-high latitudes in the middle cloud. At low latitudes, H₂SO₄ and H₂O vapors, cloud mass loading and acidity show semidiurnal variations at different altitude ranges, which can be validated against future missions. Our model emphasizes the complexity of the Venus climate system and the great need for more observations and simulations to unravel its spatial variability and underlying atmospheric and/or geological processes.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JE008088","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141841950","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":"One Martian Year of Near-Surface Temperatures at Jezero From MEDA Measurements on Mars2020/Perseverance","authors":"A. Munguira,&nbsp;R. Hueso,&nbsp;A. Sánchez-Lavega,&nbsp;D. Toledo,&nbsp;M. de la Torre Juárez,&nbsp;A. Vicente-Retortillo,&nbsp;G. M. Martínez,&nbsp;T. Bertrand,&nbsp;T. del Rio-Gaztelurrutia,&nbsp;E. Sebastián,&nbsp;M. Lemmon,&nbsp;J. Pla-García,&nbsp;J. A. Rodríguez-Manfredi","doi":"10.1029/2024JE008385","DOIUrl":"https://doi.org/10.1029/2024JE008385","url":null,"abstract":"<p>Measurements of ground and near surface atmospheric temperatures at Jezero obtained during 700 sols by the Mars Environmental Dynamics Analyzer (MEDA) characterize the thermal behavior of the near surface Martian atmosphere during a full Martian Year. The seasonal evolution of MEDA measurements is compared with predictions from the Mars Climate Database and the solar irradiance at the surface. Thermal tides observed in the daily cycle of temperatures follow a seasonal cycle with additional variations greater than 2 K on time-scales of tens of sols. We also observe sol-to-sol variations of about 1 K in mean daily air temperatures in autumn and winter with periodicities of 4–7 sols that might be related to baroclinic disturbances that are frequent in those seasons at high latitudes. We examine the evolution of the vertical thermal gradient and temperature fluctuations without finding a seasonal response to irradiance and dust load. We find that the convective boundary layer becomes isothermal and collapses 1 hr before sunset except during northern hemisphere winter, when the collapse occurs closer to sunset, implying a longer duration of the daytime convective instability. Around this period, the rover was located in the delta front in a location of complex topography where we observed stronger thermal gradients and intense daytime air temperature fluctuations. We also find in this place a nighttime event of gravity waves on near-surface air temperatures, with amplitudes of 2 K and periods of 10 min. These waves possibly propagate downward through a near isothermal stable layer.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008385","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141736843","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":"Variable Iron Mineralogy and Redox Conditions Recorded in Ancient Rocks Measured by In Situ Visible/Near-Infrared Spectroscopy at Jezero Crater, Mars","authors":"L. Mandon,&nbsp;B. L. Ehlmann,&nbsp;R. C. Wiens,&nbsp;B. J. Garczynski,&nbsp;B. H. N. Horgan,&nbsp;T. Fouchet,&nbsp;M. Loche,&nbsp;E. Dehouck,&nbsp;P. Gasda,&nbsp;J. R. Johnson,&nbsp;A. Broz,&nbsp;J. I. Núñez,&nbsp;M. S. Rice,&nbsp;A. Vaughan,&nbsp;C. Royer,&nbsp;F. Gómez,&nbsp;A. M. Annex,&nbsp;O. Beyssac,&nbsp;O. Forni,&nbsp;A. Brown,&nbsp;J. F. Bell III,&nbsp;S. Maurice","doi":"10.1029/2023JE008254","DOIUrl":"https://doi.org/10.1029/2023JE008254","url":null,"abstract":"<p>Using relative reflectance measurements from the Mastcam-Z and SuperCam instruments on the Mars 2020 <i>Perseverance</i> rover, we assess the variability of Fe mineralogy in Noachian/Hesperian-aged rocks at Jezero crater. The results reveal diverse Fe³⁺ and Fe²⁺ minerals. The igneous crater floor, where small amounts of Fe³⁺-phyllosilicates and poorly crystalline Fe³⁺-oxyhydroxides have been reported, is spectrally similar to most oxidized basalts observed at Gusev crater. At the base of the western Jezero sedimentary fan, new spectral type points to an Fe-bearing mineral assemblage likely dominated by Fe²⁺. By contrast, most strata exposed at the fan front show signatures of Fe³⁺-oxides (mostly fine-grained crystalline hematite), Fe³⁺-sulfates (potentially copiapites), strong signatures of hydration, and among the strongest signatures of red hematite observed in situ, consistent with materials having experienced vigorous water-rock interactions and/or higher degrees of diagenesis under oxidizing conditions. The fan top strata show hydration but little to no signs of Fe oxidation likely implying that some periods of fan construction occurred either during a reduced atmosphere era or during short-lived aqueous activity of liquid water in contact with an oxidized atmosphere. We also report the discovery of alternating cm-scale bands of red and gray layers correlated with hydration and oxide variability, which has not yet been observed elsewhere on Mars. This could result from syn-depositional fluid chemistry variations, possibly as seasonal processes, or diagenetic overprint of oxidized fluids percolating through strata having variable permeability.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JE008254","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141736840","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":"Characterizing Hydrated Sulfates and Altered Phases in Jezero Crater Fan and Floor Geologic Units With SHERLOC on Mars 2020","authors":"Yu Yu Phua,&nbsp;Bethany L. Ehlmann,&nbsp;Sandra Siljeström,&nbsp;Andrew D. Czaja,&nbsp;Pierre Beck,&nbsp;Stephanie Connell,&nbsp;Roger C. Wiens,&nbsp;Ryan S. Jakubek,&nbsp;Rebecca M. E. Williams,&nbsp;Maria-Paz Zorzano,&nbsp;Michelle E. Minitti,&nbsp;Alyssa C. Pascuzzo,&nbsp;Kevin P. Hand,&nbsp;Rohit Bhartia,&nbsp;Linda C. Kah,&nbsp;Lucia Mandon,&nbsp;Joseph Razzell Hollis,&nbsp;Eva L. Scheller,&nbsp;Sunanda Sharma,&nbsp;Andrew Steele,&nbsp;Kyle Uckert,&nbsp;Kenneth H. Williford,&nbsp;Anastasia G. Yanchilina","doi":"10.1029/2023JE008251","DOIUrl":"https://doi.org/10.1029/2023JE008251","url":null,"abstract":"<p>The Mars 2020 Perseverance rover has explored fluvio-lacustrine sedimentary rocks within Jezero crater. Prior work showed that igneous crater floor Séítah and Máaz formations have mafic mineralogy with alteration phases that indicate multiple episodes of aqueous alteration. In this work, we extend the analyses of hydration to targets in the Jezero western fan delta, using data from the SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals) Raman spectrometer. Spectral features, for example, sulfate and hydration peak positions and shapes, vary within, and across the crater floor and western fan. The proportion of targets with hydration associated with sulfates was approximately equal in the crater floor and the western fan. All hydrated targets in the crater floor and upper fan showed bimodal hydration peaks at ∼3,200 and ∼3,400 cm⁻¹. The sulfate symmetric stretch at ∼1,000 cm⁻¹ coupled with a hydration peak at ∼3,400 cm⁻¹ indicate that MgSO₄·<i>n</i>H₂O (2 &lt; <i>n</i> ≤ 5) is a likely hydration carrier phase in all units, perhaps paired with low-hydration (<i>n</i> ≤ 1) amorphous Mg-sulfates, indicated by the ∼3,200 cm⁻¹ peak. Low-hydration MgSO₄·<i>n</i>H₂O (<i>n</i> = 1–2) are more prevalent in the fan, and hydrated targets in the fan front only had one peak at ∼3,400 cm⁻¹. While anhydrite co-occurs with hydrated Mg-sulfates in the crater floor and fan front, hydrated Ca-sulfates are observed instead at the top of the upper fan. Collectively, the data imply aqueous deposition of sediments with formation of salts from high ionic strength fluids and subsequent aridity to preserve the observed hydration states.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JE008251","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141732560","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":"Volatile Transport on Ariel and Implications for the Origin and Distribution of Carbon Dioxide on Uranian Moons","authors":"Stephanie M. Menten,&nbsp;Michael M. Sori,&nbsp;Ali M. Bramson,&nbsp;Tom A. Nordheim,&nbsp;Richard J. Cartwright","doi":"10.1029/2024JE008376","DOIUrl":"https://doi.org/10.1029/2024JE008376","url":null,"abstract":"<p>The moons of Uranus have only been visited once by Voyager 2 during its 1986 flyby. Earth-based telescopic observations show a spectral signature of carbon dioxide ice on the Uranian moons Ariel, Umbriel, Titania, and Oberon, with a somewhat higher abundance on their trailing hemispheres. The inner major moon Ariel exhibits the strongest carbon dioxide ice absorption bands, which then decrease in strength with increasing orbital distance from Uranus, with the outer major moon Oberon exhibiting the weakest absorption bands. Previous work has suggested that these hemispherical and radial trends result from radiolytic production of carbon dioxide ice from interactions between the moons' surfaces and charged particles trapped in Uranus' magnetosphere. Here, we use volatile transport modeling to characterize a possible migration cycle of carbon dioxide on Ariel. We find that carbon dioxide is readily mobilized toward Ariel's equator, and that existing topography such as canyons are locations of favorable deposition for carbon dioxide ice. We predict the presence of carbon dioxide ice deposits on the floors of Ariel's canyons. Our work suggests two possible classes of sources of carbon dioxide: an active source, which may be consistent with either radiolytic production from Uranus' magnetosphere or outgassing from Ariel's interior, or an ancient source that produced CO₂ that still exists in stable canyon deposits. A future Uranus orbiter could determine which hypothesis is most likely, or if carbon dioxide could be found both in the form of ice deposits on the surface and in a global exosphere.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008376","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141730252","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":"A Proposed Model for Cryovolcanic Activity on Enceladus Driven by Volatile Exsolution","authors":"Karl L. Mitchell,&nbsp;Jason Rabinovitch,&nbsp;Jonathan C. Scamardella,&nbsp;Morgan L. Cable","doi":"10.1029/2023JE007977","DOIUrl":"https://doi.org/10.1029/2023JE007977","url":null,"abstract":"<p>There is considerable interest in sending a mission to Enceladus to sample its erupting materials, which are sourced from its ocean, a proposed habitable environment. However, we lack resolution between competing ascent and eruption models, which offer differing consequences and challenges for mission sampling and access strategies. We report a new Enceladus ascent and eruption model, “Cryo-Erupt,” where ascent from ocean to jet is driven by the exsolution and expansion of dissolved gases from ascending water within conduits. This mechanism shares many similarities with some forms of terrestrial activity, including explosive silicate volcanism, cold-water geysers and “limnic” eruptions. This preliminary study suggests that this mode of ascent and eruption is viable and broadly consistent with a range of observations including the apparent co-existence of point- (jet) and fissure- (curtain) sourced activity as well as strong contrasts in velocity and ice-to-vapor ratio between the plume and the jets feeding it. However, it requires the co-existence of a sublimation plume as an additive component to the broader plume. The outcomes of the Cryo-Erupt model differ in terms of conduit physical and chemical processes from previously proposed boiling interface eruption models, for example, predicting larger dynamic pressures and narrower conduits, which could present challenges for direct robotic access. Due to the lack of a static boiling interface or wall condensation, bulk composition is unlikely to change appreciably during ascent from the ocean-conduit interface to the jet, potentially simplifying the interpretation of samples collected in space or on Enceladus’ surface.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141639655","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 Gravity Wave-Seeded Ionospheric Irregularities in the Martian Ionosphere","authors":"Rong Tian,&nbsp;Chunhua Jiang,&nbsp;Beatriz Sánchez-Cano,&nbsp;Wenjie Yin,&nbsp;Guobin Yang,&nbsp;Tongxin Liu,&nbsp;Yaogai Hu","doi":"10.1029/2024JE008323","DOIUrl":"https://doi.org/10.1029/2024JE008323","url":null,"abstract":"<p>For the past few decades, it has been demonstrated that gravity waves (GWs) and neutral winds can drive ionospheric irregularities on Earth. Still, as far as we know, the formation of ionospheric irregularities on Mars due to GWs has not been well studied. In this study, we use data from the NASA's Mars Atmosphere and Volatile Evolution (MAVEN) mission to show evidence of an irregularity event in the Martian ionosphere, potentially seeded by the GWs break (GWB). Statistical findings indicate that the observed ratio of GWB-related irregularity events varies from ∼0.25 to ∼0.47 each year, and the average ratio in 2015–2020 is ∼0.37. We perform a numerical simulation to provide further insight into the processes behind irregularity formation, which employs neutral wind shear as a source of perturbation in the context of the GWB. The simulations yield results fundamentally aligned with the observed characteristics of ionospheric irregularities in the 2018 event by considering the wind shear as the disturbance source. This study provides supplementary insights into the perturbation sources involved in shaping irregularities within the Martian ionosphere and presents valuable information about the coupling between the Martian ionosphere and the lower atmosphere.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141624532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Geological History of Enceladus' Cratered Terrains","authors":"Mallory J. Kinczyk,&nbsp;Paul K. Byrne,&nbsp;Gerald W. Patterson","doi":"10.1029/2024JE008326","DOIUrl":"https://doi.org/10.1029/2024JE008326","url":null,"abstract":"<p>This study presents a comprehensive assessment of the geomorphology, crater distributions, and tectonic structures within Enceladus' cratered terrains. We analyzed the distributions of impact craters and tectonic structures in seven regions of interest to inform an interpretation of the geological history of this terrain in the context of Enceladus' global evolution. We found that the tectonic structures, including both ancient, subdued troughs and young, narrow fractures, point to a cratered terrain that not only experienced early tectonic modification but also shows evidence of recent geological activity. Ancient troughs present in the equatorial cratered terrains are similar in scale and orientation to troughs present in the Leading and Trailing Hemisphere Terrains, an observation that supports possible non-synchronous rotation of the ice shell. A dearth of impact craters in the equatorial regions as identified previously does not hold for craters &lt;3 km in diameter in the anti-Saturnian hemisphere. The anomalous presence of excess small craters in this region could be due to secondary or sesquinary impacts from a catastrophic event occurring at Enceladus or a neighboring moon. Finally, narrow fractures are pervasive across the cratered terrains and are most commonly oriented parallel or sub-parallel to the most proximal cratered terrain boundary. This directionality of pervasive recent fracturing could be related to the vertical movement of an isostatically uncompensated ice shell. Enceladus' cratered terrains provide insight into the long-term evolution of the satellite, an important component to assessing its role in Solar System evolution and its potential for habitability.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008326","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141624289","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}