Journal of Geophysical Research: Planets最新文献

{"title":"Initial Thermal States of Super-Earth Exoplanets and Implications for Early Dynamos","authors":"Nathaniel I. White,&nbsp;Jie Li","doi":"10.1029/2024JE008550","DOIUrl":"https://doi.org/10.1029/2024JE008550","url":null,"abstract":"<p>The accretion of Earth and the formation of a metallic core released a large amount of primordial heat and may have enabled its evolution into a habitable world. Metal-silicate segregation likely occurs in super-Earth exoplanets as well, but its influence on their initial thermal states has not been fully examined. Here we calculated the energy released during core-mantle differentiation of super-Earths for a range of planet radii and core mass fractions. We found that the energy of differentiation increases with planet mass for rocky planets with Earth-like composition, and it peaks at 55% core by mass in Earth-sized rocky planets. Using the latest mineral physics constraints on the equations-of-state and melting curve of relevant phases, we modeled the initial thermal profiles and assessed the extent of melting in initial iron cores for plausible heat retention efficiencies. Our results suggest that following accretion and metal-silicate differentiation, the cores of most super-Earths are expected to be at least partially molten, a necessary condition for the generation of a magnetic field. Based on the largely molten state of Earth's core at the present day, we place a lower bound of 7% retention of accretional energy as primordial heat in rocky planets.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 2","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008550","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143475421","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":"WindSightNet: The Inter-Annual Variability of Martian Winds Retrieved From InSight's Seismic Data With Machine Learning","authors":"Alexander E. Stott,&nbsp;Raphael F. Garcia,&nbsp;Naomi Murdoch,&nbsp;David Mimoun,&nbsp;Mélanie Drilleau,&nbsp;Claire Newman,&nbsp;Aymeric Spiga,&nbsp;Don Banfield,&nbsp;Mark Lemmon,&nbsp;Sara Navarro,&nbsp;Luis Mora-Sotomayor,&nbsp;Constantinos Charalambous,&nbsp;William T. Pike,&nbsp;Philippe Lognonné,&nbsp;William B. Banerdt","doi":"10.1029/2024JE008695","DOIUrl":"https://doi.org/10.1029/2024JE008695","url":null,"abstract":"<p>Wind measurements from landed missions on Mars are vital to characterize the near surface atmospheric behavior on Mars and improve atmospheric models. These winds are responsible for aeolian change and the mixing of dust in and out of the atmosphere, which has a significant effect on global circulation. The NASA InSight mission recorded wind data for around 750 sols. The seismometer, however, recorded data for around 1400 sols. The dominant source of energy in the seismic data is in fact due to winds. To this end, we propose a machine learning model, dubbed WindSightNet, to map the seismic data to wind speed and direction. The trained network achieves wind speed and direction measurements with errors of 0.932 m/s and 32.6°. We use WindSightNet to retrieve winds from the entire time the seismometer was recording to compare year-to-year wind variations at InSight. The continuous nature of the data set enables the extraction of periodic behavior. We observe a pattern of waves due to baroclinic activity with periods of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>2–3, <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>4, <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>5–7 and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>9–20 sols occurring <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>L</mi>\u0000 <mi>s</mi>\u0000 </msub>\u0000 <mo>=</mo>\u0000 </mrow>\u0000 <annotation> ${L}_{s}=$</annotation>\u0000 </semantics></math>180–360°. We also observe periodicity during the day due to convective cells. This is used to estimate the boundary layer height, yielding values between 2.3 and 7.7 km. A data-science based metric is proposed to provide a quantification of the year-to-year differences in the wind speeds. This highlights variations linked to dust activity as well as other transient differences. On the whole, the seismic-derived winds confirm the dominance of the global circulation leading to repeatable weather patterns.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 2","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008695","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143466301","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":"Mercury's Field-Aligned Currents: Perspectives From Hybrid Simulations","authors":"Z. Shi,&nbsp;Z. J. Rong,&nbsp;S. Fatemi,&nbsp;C. F. Dong,&nbsp;Lucy Klinger,&nbsp;J. W. Gao,&nbsp;J. A. Slavin,&nbsp;F. He,&nbsp;Y. Wei,&nbsp;M. Holmström,&nbsp;S. Barabash","doi":"10.1029/2024JE008610","DOIUrl":"https://doi.org/10.1029/2024JE008610","url":null,"abstract":"<p>Previous studies suggested that Mercury's magnetosphere could possess Earth-like field-aligned currents (FACs) despite the absence of an ionosphere. However, due to the limited coverage of spacecraft observations, our understanding of Mercury's FACs is scarce. Here, we employed Amitis, a hybrid-kinetic plasma model, to investigate the establishment and global pattern of Mercury's FACs. The responses of Mercury's FACs to various interior conductivity profiles and different orientations of the upstream interplanetary magnetic field (IMF) were simulated. It has been shown that the profile of a less resistive upper layer and a conducting core favors the establishment of FACs. Three types of large-scale FACs (Region 1-like, Region 2-like and NBZ-like FACs) are shown in simulations. Comparison with previous observations suggests that Mercury's effective conductance for closing R1-like FACs is ∼2.4–3.4 S. The influence of IMF orientation on FACs is similar to that observed in Earth's magnetosphere, but the response of the R2-like FACs to the IMF orientation is different.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 2","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143466166","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":"Evolution of Plume Volcanism at Atla Regio, Venus","authors":"P. J. Mason,&nbsp;A. Klidaras,&nbsp;D. Cirium,&nbsp;R. C. Ghail,&nbsp;S. Lea-Wurzbach","doi":"10.1029/2024JE008815","DOIUrl":"https://doi.org/10.1029/2024JE008815","url":null,"abstract":"<p>Atla Regio is a large topographic rise, at the equator of Venus, considered to sit above a young mantle upwelling. Hosting several giant shield volcanoes, including Maat Mons, it is a strong candidate for recent eruptive activity. Through detailed analysis of material units and structures at Ozza, Maat and Sapas Mons, northern Dali Chasma and the surrounding plains, we have unraveled the tectono-magmatic evolution at Atla Regio. Lithostratigraphic analysis, of the volcanic styles, lava flow relationships, rift–associated shield clusters, graben-fissure systems and pit cratering, in relation to the regional plains and other older features, has enabled the establishment of a model of the evolution of volcanism. Structural analysis reveals that graben-fissure systems at Ozza Mons transition outward into three major rifts, and two new, unnamed volcanoes are identified. Our model is evidenced by analysis of lava flow stratigraphy and cross-cutting relationships with respect to the stratigraphic marker provided by the ejecta halo of the Uvaysi impact, and using sound stratigraphic principles. A relative chronostratigraphic framework for the area around Ozza and Maat Mons has thus been constructed, and our findings are in agreement with prior research. A new regional history is proposed here, where volcanism was initially concentrated along Dali Chasma, before plume volcanism took over at Ozza Mons and finally, Maat Mons became the most recent locus of volcanism. We propose that the pattern of large shield volcanoes with displaced centers here is indicative of minor crustal adjustments above a relatively long-lived mantle plume.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 2","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008815","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143466302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Constraining 2.0 Ga Volcanism on the Moon via 40Ar/39Ar Dating of Chang'e-5 Basalts","authors":"Fei Su,&nbsp;Xuhang Zhang,&nbsp;Youjuan Li,&nbsp;Brian R. Jicha,&nbsp;Katherin H. Joy,&nbsp;Qiuli Li,&nbsp;Yi Chen,&nbsp;Shuhui Cai,&nbsp;Runchuan Liu,&nbsp;Qin Zhou,&nbsp;Saihong Yang,&nbsp;Xianhua Li,&nbsp;Liekun Yang,&nbsp;Wen Chen,&nbsp;Junjie Li,&nbsp;Wanfeng Zhang,&nbsp;Huaning Qiu,&nbsp;Huaiyu He","doi":"10.1029/2024JE008495","DOIUrl":"https://doi.org/10.1029/2024JE008495","url":null,"abstract":"<p>The Chang'e-5 landing site provides an important window into the Moon's late Eratosthenian period of volcanism at ∼2 Ga. Clarifying the Moon's history of volcanic activity using radioisotopic dating assists investigations of the evolution of the lunar surface as well as the Moon's internal dynamics. Recent chronological investigations of Chang'e-5 basalts produced ages spanning ∼100 Ma, thereby inhibiting interpretation of the duration of volcanism recorded in the returned samples. We used microcomputed tomography and Back-Scatter Electron imaging to characterize the structure and morphology of nine Chang'e-5 basalt clasts. Several basalt clasts lack shock features and are interpreted to have not been significantly thermally disturbed. ⁴⁰Ar/³⁹Ar incremental heating produced well defined plateaus for four sub-split samples that give a weighted mean age of 2,021 ± 17 Ma (2σ). These are among the youngest mare basalts to be dated thus far by the ⁴⁰Ar/³⁹Ar method and, when combined with most of the published Pb-Pb ages for Chang'e-5 basalts, define a single episode of mare volcanism at ∼2,021 Ma.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 2","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008495","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143456054","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":"Wavelet Multi-Scale Analysis of the Linear Gravity Anomalies of the Moon","authors":"Yan Wan,&nbsp;Bo Chen,&nbsp;Changyi Xu,&nbsp;Jinsong Du","doi":"10.1029/2024JE008427","DOIUrl":"https://doi.org/10.1029/2024JE008427","url":null,"abstract":"<p>The history of the thermal and dynamic evolution of the Moon is partly recorded by lunar linear structures. Identification and analysis of subsurface linear structures and their associated gravity anomalies provide insights into the early evolution of the Moon. However, the current understanding of their deep extensions is limited. In this study, we employ gravity data and the 2D continuous wavelet transform technique to analyze the subsurface extension of linear structures. Four significant linear gravity anomalies (LGAs) are studied, including the north (FN) and south (FS) anomalies located in the lunar farside and the northwest (NNW) and northeast (NNE) anomalies in the nearside. Our results indicate that the top depths and widths of the mass sources associated with these linear structures can be determined. The intrusion depths of all four LGAs vary along their strike, with the shallowest intrusion depth reaching 8–10 km. For the FN anomaly, the top depths of the intrusive body range from 8 to 20 km, while intrusion widths vary between 30 and 50 km. Wavelet analysis for the FS anomaly indicates an intrusive source with a top width and depth of ∼30 and 10 km. For the NNW anomaly, the source body has top depths of 10–20 km with varying top widths at different sections (25∼50 km). As for the NNE structure, our results suggest substantial top widths between 75 and 150 km alongside relatively shallow top depths of 8–15 km. These LGAs are likely attributed to vertical magma intrusions connected at their bases to the crust-mantle interface.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 2","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143455884","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":"Topographical Analysis of Libya Linea on Europa: Geologic Evolution and Identification of a New Putative Cryovolcanic or Diapir Field","authors":"Pietro Matteoni,&nbsp;Gianluca Chiarolanza,&nbsp;Giuseppe Mitri,&nbsp;Ralf Jaumann,&nbsp;Jon Hillier,&nbsp;Frank Postberg","doi":"10.1029/2024JE008324","DOIUrl":"https://doi.org/10.1029/2024JE008324","url":null,"abstract":"<p>On Jupiter's icy moon Europa, bands played a crucial role in its geological evolution. Large-scale bands such as Libya Linea (LL), which has previously not been studied with an applied method as other prominent Europan bands, offer insights into the icy moon's regional geologic history. To unravel the evolution of LL, our study employed a detailed topographic analysis, complementing a previous tectonic reconstruction (Collins et al., 2022, https://doi.org/10.1029/2022JE007492). While said reconstruction provided a comprehensive view of western LL's tectonic evolution, our study introduces a critical topographic dimension, revealing nuanced differences and emphasizing the importance of an investigation that included LL's eastern portions. We identified distinctive topographic signatures indicative of different deformation stages. The analysis of eastern LL, previously not studied in detail, allowed us to define and characterize the topographic signatures of younger and older parts of LL. In western LL, the topographic characteristics of some branches of LL aligned with those of young branches in its eastern parts, while the topographic signatures in other LL branches supported their previous interpretation as formed during early and intermediate deformation stages. Furthermore, the identification of transpressive features in western LL partially challenged the previous reconstruction, suggesting reworking processes at late evolutionary stages. Overall, our integrated topographic and morpho-stratigraphic analysis broadens the understanding of LL's evolution and bands on Europa in general. Additionally, the identification of a small area of putative cryovolcanic or diapiric activity adds intriguing elements for future exploration of this region with the Europa Clipper and JUICE spacecraft.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 2","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008324","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143439059","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":"Electrical Properties of Alkaline Earth Sulfides and Implications for the Interior of Mercury","authors":"Anne Pommier,&nbsp;Michael J. Tauber,&nbsp;Christian Renggli,&nbsp;Christopher Davies,&nbsp;Alfred Wilson","doi":"10.1029/2024JE008651","DOIUrl":"https://doi.org/10.1029/2024JE008651","url":null,"abstract":"<p>Alkaline earth sulfides are possibly abundant in the mantle of Mercury, and knowledge of their melting and transport properties is needed to investigate the structure of the planet. We report electrical experiments at pressures in the range 2–5 GPa and at temperatures up to ∼2,400 K on proposed analogs of natural sulfides, that is, Ca_1-xMg_xS with minor impurities. Electrical conductivity increases nonuniformly with temperature with no systematic dependence on cation composition. At relatively low temperatures (near 1,100 K), the conductivities span a wide range, whereas at higher temperatures the values converge within ∼0.5–7 S/m at 1,800 K and 5 GPa. The conductivity trends are complex, and likely reflect contributions from divalent cations, alkali metal and carbon impurities, which would similarly contribute to the conductivity of Mercury's crust and mantle. Melting is identified by a sharp increase in conductivity between ∼1,850 and 2,100 K at 5 GPa. These transition temperatures are consistent with the presence of impurities. Using electrical studies on relevant silicate minerals and petrological observations, we developed electrical conductivity-depth profiles of Mercury's silicate portion. Depending on the interconnectivity of the sulfide phase, the conductivity at the base of the mantle containing 8 vol.% sulfide ranges from ∼0.2 to &gt;8 S/m. Our results can be tested with future observations from the ESA-JAXA BepiColombo mission.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 2","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143431702","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":"Hollows on Mercury: Global Classification of Degradation States and Insight Into Hollow Evolution","authors":"Ariel N. Deutsch,&nbsp;Valentin T. Bickel,&nbsp;David T. Blewett","doi":"10.1029/2024JE008747","DOIUrl":"https://doi.org/10.1029/2024JE008747","url":null,"abstract":"<p>Hollows are small, shallow, irregularly shaped landforms, widespread across Mercury, interpreted to have formed via loss of volatiles. Here, we present the first global analysis of hollow degradation states using a new machine learning-derived global catalog. We define three classes, grading from younger/potentially active “Stage 1” (sharp morphology, high visible reflectance) to older/potentially expired “Stage 3” (softened morphology, reflectance similar to that of surroundings). Most analyzed hollows are Stage 1 (<i>N</i> = 1,545 individual hollows), which are more common than Stage 2 (<i>N</i> = 1,111) or Stage 3 (<i>N</i> = 10) hollows near the equator, consistent with the idea that insolation is a primary driver for hollow initiation/growth. Areas where Stage 2 hollows are more common than Stage 1 hollows may indicate regions of relative volatile depletion. Stage 3 hollows are rare, suggesting they are systematically missed during image review, or that hollows on Mercury are mostly young, have been recently reactivated, or are quickly erased once they become inactive. Temperature may limit hollow growth, given that only small hollows are identified in the coldest terrains. There is no meaningful difference in the distribution of hollow sizes between stages, suggesting that their morphological and reflectance properties are not substantially muted until they are fully grown. Stage 1 hollows are more commonly found on steeper slopes than nearby Stage 2 hollows, suggesting that slopes may be an important control on how long hollows remain active. Our hollow classifications are openly available and can help to inform global-scale studies of hollow evolution, and upcoming targeting efforts by the ESA/JAXA BepiColombo mission.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 2","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008747","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143431782","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":"Inefficient Loss of Moderately Volatile Elements From Exposed Planetesimal Magma Oceans","authors":"Zhongtian Zhang,&nbsp;Peter E. Driscoll","doi":"10.1029/2024JE008671","DOIUrl":"https://doi.org/10.1029/2024JE008671","url":null,"abstract":"&lt;p&gt;Some melted and differentiated planetesimals, such as the parent bodies of angrites and howardite-eucrite-diogenite meteorites, are severely depleted in moderately volatile elements (MVEs). The origins of these depletions are critical for understanding early solar system evolution but remain topics of debate. Numerous previous studies have invoked evaporation from magma oceans as a potential mechanism for producing these depletions, yet this process is poorly explored. In this study, we examine the efficiency of MVE loss from planetesimal magma oceans. Upon heating from short-lived &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mmultiscripts&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;A&lt;/mi&gt;\u0000 &lt;mi&gt;l&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;none&gt;&lt;/none&gt;\u0000 &lt;none&gt;&lt;/none&gt;\u0000 &lt;mprescripts&gt;&lt;/mprescripts&gt;\u0000 &lt;none&gt;&lt;/none&gt;\u0000 &lt;mn&gt;26&lt;/mn&gt;\u0000 &lt;/mmultiscripts&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${}^{26}mathrm{A}mathrm{l}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, internal magma oceans can develop beneath insulating crusts. The magma oceans may be exposed to the surface by collisional disruption of the crusts, but would be rapidly cooled by the cold environments. The exposed surface would be quenched to solid/glass; even if the quenched skin can be recycled by convection such that the magma ocean can be continuously resurfaced, only a small portion of the surface can remain molten. In the convection boundary layer, “vertical” advection is suppressed, energy and element transports toward the surface occur via thermal and chemical diffusion (if MVEs do not exsolve as bubbles). As chemical diffusivity is much smaller than thermal diffusivity, MVE transport is much less efficient than heat transport, and MVE loss during magma ocean cooling is likely minimal (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;≲&lt;/mo&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;mi&gt;%&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $lesssim 1%$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; the total inventory). Therefore, MVE depletions may not be easily explained by evaporation from &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mmultiscripts&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;A&lt;/mi&gt;\u0000 &lt;mi&gt;l&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;none&gt;&lt;/none&gt;\u0000 &lt;none&gt;&lt;/none&gt;\u0000 &lt;mprescripts&gt;&lt;/mprescripts&gt;\u0000 &lt;none&gt;&lt;/none&gt;\u0000 &lt;mn&gt;26&lt;/mn&gt;\u0000 &lt;/mmultiscripts&gt;\u0000 &lt;","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 2","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143396803","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}