Journal of Geophysical Research: Planets最新文献

{"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}

{"title":"Shock Induced Metal Globules in Chang'e-5 Impact Melt Splash and Implication for the Coalescence Growth of Submicroscopic Metal Particles in Lunar Soil","authors":"Chengxiang Yin,&nbsp;Xiaohui Fu,&nbsp;Haijun Cao,&nbsp;Xuejin Lu,&nbsp;Jian Chen,&nbsp;Jiang Zhang,&nbsp;Zongcheng Ling,&nbsp;Xiaochao Che","doi":"10.1029/2024JE008733","DOIUrl":"https://doi.org/10.1029/2024JE008733","url":null,"abstract":"<p>Submicroscopic metallic iron particles (SMFe) are unique components of lunar soil produced during long-term exposure on the Moon's surface. They can significantly alter the optical properties of lunar soil and this alteration is crucial for the interpretation of remote sensing data. The origin and formation of SMFe remain a subject of controversy, with multiple competing mechanisms coexisting. The newly returned Chang'e-5 (CE-5) samples provide a new opportunity to elucidate the formation of SMFe. Here, we conducted a systematical study on the morphology and chemical characteristics of metal globules in CE-5 impact melt splash. A total of 30,630 metal globules were identified with an average diameter of 222.87 nm. Most of them are nearly/perfectly spherical, but the others are irregular in shape. Three types of irregular metal globules have been found: Spindle type, deformation type, and coalescence type. Spindle and deformation types were formed under the influence of local thermal disequilibrium and/or differences in wettability, while the coalescence type reflects the growth of metal globules driven by the Oswald ripening. A series of metal globules at different coalescence stages were found, providing conclusive petrographic evidence for the long-term hypothesis of SMFe growth (e.g., Pieters &amp; Noble, 2016, https://doi.org/10.1002/2016je005128). Geochemical analysis shows that meteoritic Fe-Ni metals (like iron meteorite) made a significant contribution to the formation of metal globules. This further indicates the contribution of exotic meteoroid materials to the CE-5 lunar soil.</p>","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":"143396804","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":"Recent Tectonic Activity in and Around the Posidonius Crater, Moon","authors":"K. B. Kimi,&nbsp;S. Vijayan,&nbsp;K. S. Sharini,&nbsp; Harish,&nbsp;S. Tuhi,&nbsp;Anil Chavan,&nbsp;R. K. S. Priya","doi":"10.1029/2024JE008446","DOIUrl":"https://doi.org/10.1029/2024JE008446","url":null,"abstract":"<p>Tectonic structures such as wrinkle ridges, lobate scarps, small-scale graben, and tectonic pits reveal the recent lunar activity and complex deformational processes. Despite numerous studies, the northeastern region of the Mare Serenitatis basin, including the Posidonius crater, has yet to be studied in detail. This research presents a comprehensive analysis of tectonic structures in this region, revealing ∼808 km of wrinkle ridges, ∼286 km of lobate scarps, ∼346 km of small-scale graben, and ∼269 tectonic pits. We identified 412 craters deformed by wrinkle ridges, 55 craters by lobate scarps, and 108 craters by small-scale graben, suggesting extensive recent deformation. Chronological analysis of wrinkle ridges and lobate scarps revealed young ages ranging from <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msubsup>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 <mn>29</mn>\u0000 </mrow>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>9</mn>\u0000 </mrow>\u0000 <mrow>\u0000 <mo>+</mo>\u0000 <mn>10</mn>\u0000 </mrow>\u0000 </msubsup>\u0000 </mrow>\u0000 <annotation> ${sim 29}_{-9}^{+10}$</annotation>\u0000 </semantics></math> Ma to ∼120 ± 30 Ma close to the crater, whereas Posidonius crater resurfaced floor age tend to <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 <msubsup>\u0000 <mn>2.8</mn>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>0.5</mn>\u0000 </mrow>\u0000 <mrow>\u0000 <mo>+</mo>\u0000 <mn>0.4</mn>\u0000 </mrow>\u0000 </msubsup>\u0000 </mrow>\u0000 <annotation> ${sim} {2.8}_{-0.5}^{+0.4}$</annotation>\u0000 </semantics></math> Ga. Our study suggests that the blind thrust fault deformed the western floor of the Posidonius crater, with small-scale graben with pits plausibly developed during the reactivation. Orthogonal transitions that occur between adjacent wrinkle ridges and lobate scarps in the study area could be a splay fault of the blind thrust fault and likely formed during the reactivation. This reactivation plausibly resulted from a combination of recession stresses, diurnal tidal stresses, and global contraction. Additionally, a combination of complex processes─intrusion, subsidence, and tectonics associated with the blind thrust fault plausibly influenced Rima Posidonius. Overall, this study suggests that the northeastern region of the Mare Serenitatis basin witnessed recent tectonic activity and could be a potential site for future exploration missions.</p>","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":"143396805","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":"Short-Period Flapping Motion of Current Sheet in Saturn's Magnetosphere","authors":"S. B. Xu,&nbsp;S. Y. Huang,&nbsp;Z. G. Yuan,&nbsp;K. Jiang,&nbsp;H. H. Wu,&nbsp;J. Zhang,&nbsp;Z. Wang,&nbsp;Q. Y. Xiong,&nbsp;R. T. Lin","doi":"10.1029/2024JE008682","DOIUrl":"https://doi.org/10.1029/2024JE008682","url":null,"abstract":"<p>The flapping motion of the current sheet is a common dynamic phenomenon in the planetary magnetosphere and plays an important role in the transportation of energy and disturbances. Based on the measurements from the Cassini spacecraft, we investigate the short-period flapping motions of the current sheet characterized by periods significantly much smaller than the planetary rotation cycle in Saturn's magnetosphere. Employing the Minimum Variance Analysis (MVA) method, a new technique is developed to distinguish the propagation of current sheet flapping in the radial and azimuthal directions. A total of 105 short-period current sheet flapping events have been detected in Saturn's magnetosphere. The global spatial distribution of these events is provided, and their respective propagation directions have been identified. Further discussions are conducted on the potential sources of the short-period current sheet flapping in Saturn's magnetosphere, including magnetic reconnection, Titan, fast plasma flow, planetary period oscillations, and instabilities near the magnetopause.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 2","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143380793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shallow Subsurface Water at the Base of Europa's Double Ridges","authors":"G. Steinbrügge,&nbsp;G. Patterson","doi":"10.1029/2024JE008673","DOIUrl":"https://doi.org/10.1029/2024JE008673","url":null,"abstract":"<p>Recent numerical modeling and the detection of an Earth analog advanced our understanding of the formation mechanisms behind Europa's distinctive double ridges. Notably, a recent contribution by Cashion et al. (2024, https://doi.org/10.1029/2023je008007), demonstrated that ice wedging as a primary formation mechanism can accurately reproduce the topographic characteristics of double ridges. Building on previous theoretical foundations laid by Melosh and Turtle (2004, https://ui.adsabs.harvard.edu/abs/2004LPI….35.2029M/abstract), it hints at a complex hydrological system within the ice shell, characterized by local reservoirs and cycles of freezing that could also explain other observed geological formations, such as lenticulae and chaos terrain. This dynamic suggests the possibility of material exchange processes within the ice shell of Europa and enhances our understanding of the moon's habitability.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 2","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008673","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143389043","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":"Apollo Impact Melts Record a Rapidly Declining Impact Rate in the Late Imbrian","authors":"A. M. Blevins,&nbsp;D. A. Minton,&nbsp;Y. H. Huang,&nbsp;J. Du,&nbsp;M. M. Tremblay,&nbsp;C. I. Fassett","doi":"10.1029/2024JE008722","DOIUrl":"https://doi.org/10.1029/2024JE008722","url":null,"abstract":"<p>Crater chronology functions are used to estimate absolute surface ages using the number density of observed craters. The calibration of chronology functions is done using crater counts on regions with radiometrically dated samples. Both the Neukum Production Function (NPF) and Robbins Production Function (RPF) contain lunar chronology functions anchored by Apollo and Luna samples that have measured absolute ages and are known to be from surfaces with measured crater densities. However, these functions were constructed using different data and assumptions for their respective crater counts, and their functions differ in the rate of decline during the Imbrian period (3–3.9 Ga). In particular, the RPF suggests that the decline in impact rate was much more rapid than the decline suggested by the NPF. We use a numerical impact bombardment model called CTEM to track the production and transportation of impact melts. Using CTEM, we simulated the bombardment history of the Moon under each chronology function, and calculated the age distribution of impact melts mixed in the top meter of regolith at locations corresponding to the Apollo 14–17 landing sites. These results were then compared to the age distribution of Apollo impact melts. We find the rapid decline suggested by the RPF to be a better match to the age distribution of Apollo impact melts than the gradual decline of the NPF.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 2","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008722","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143389042","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}