Journal of Geophysical Research: Planets最新文献

{"title":"The Evaluation of Space Weathering Effects on Lunar Samples From a Raman Spectroscopic Perspective","authors":"Xuejin Lu,&nbsp;Haijun Cao,&nbsp;Jian Chen,&nbsp;Changqing Liu,&nbsp;Yanqing Xin,&nbsp;Zongcheng Ling","doi":"10.1029/2024JE008780","DOIUrl":"https://doi.org/10.1029/2024JE008780","url":null,"abstract":"<p>Airless bodies within the solar system experience bombardment from the solar wind and micrometeoroids, leading to a range of physical and chemical alterations of soil materials. However, research on the Raman spectroscopic features induced using space weathering processes in returned lunar samples is limited. Such research is essential for accurately interpreting mineralogical and compositional information using Raman spectroscopy in future planetary missions. Here, we investigated the effects of space weathering on the Raman spectral features of lunar minerals from Chang'e-5 soil samples. The Raman peak intensities decrease after exposure to space weathering without significant shifts in peak position. Furthermore, fluorescence is a critical indicator for evaluating the degree of space weathering. This work demonstrates that Raman spectroscopy is complementary to visible and near-infrared spectroscopy in assessing space weathering effects and serves as a valuable tool for in situ mineralogical investigations in future space exploration missions.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 5","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143902843","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":"Characterizing Ferrihydrite Transformation Products in Near-Saturated Brine Environments: Implications for Fe-Oxide Formation on Mars","authors":"Kaydra Barbre,&nbsp;Andrew Elwood Madden,&nbsp;Caitlin Hodges,&nbsp;Megan Elwood Madden","doi":"10.1029/2024JE008650","DOIUrl":"https://doi.org/10.1029/2024JE008650","url":null,"abstract":"<p>Ferrihydrite has been observed within the Martian regolith; therefore, ferrihydrite transformation pathways are likely critical to iron cycling and mineral transformation on Mars and other extraterrestrial systems. Data from Mars rovers and orbiters indicate that ferrihydrite is associated with significant salt deposits. Previous studies show these salts likely formed as the planet desiccated and may rehydrate to form modern brines today that strongly influence(d) mineral alteration. We hypothesize that the salts observed on Mars' surface may help preserve ferrihydrite for longer periods than typically observed on Earth. This study investigates the effects of brine chemistry on ferrihydrite alteration through laboratory experiments. Lab-synthesized ferrihydrite was reacted with near-saturated brines and ultra-pure water at 20°C for 30 days in a series of batch reactor experiments. X-ray diffraction and Raman spectroscopy showed that ferrihydrite was preserved without evidence of dissolution/transformation in near-saturated solutions of MgSO₄, Na₂SO₄, and NaClO_4, while additional iron-oxyhydroxide phases formed in other brines. We also compared mineral reaction products formed from freeze-dried ferrihydrite and undried ferrihydrite slurry. The freeze-dried ferrihydrite was more likely to be preserved, whereas ferrihydrite in a slurry resulted in the precipitation of goethite and lepidocrocite, indicating that particle aggregation and/or drying history affect ferrihydrite stability and alteration. Overall, ferrihydrite remained largely unaltered in the presence of concentrated sulfate and perchlorate brines. In the context of soils/regolith observed on Mars, our research demonstrates that ferrihydrite is more likely to be preserved when found in areas where these salts are dominant, and desiccated in a cold/arid environment prior to brine exposure.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 5","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143901099","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":"Simulating Fractional Melting of the Martian Mantle Using the pMELTS Algorithm","authors":"J. Brian Balta","doi":"10.1029/2024JE008743","DOIUrl":"https://doi.org/10.1029/2024JE008743","url":null,"abstract":"<p>Despite numerous investigations, the conditions and source materials that created the shergottite meteorites have not been fully constrained. Previous models commonly fit some parameters but struggle to fully explain the observed compositions and invoke processes of crustal assimilation without a full assessment. In this work, I apply the program pMELTS to investigate how variations in melting conditions propagate to magma chemistry. I use fractional melting to simulate melt production in upwelling mantle, and test whether changes in mantle temperature, lithospheric thickness, or water content create better fits to shergottites. For both changes in mantle temperature and lithospheric thickness, the observed melt compositions never approach the shergottites in parameters such as Mg #, CaO, and Al₂O₃ contents. However, elevated mantle water leads to increasing CaO/Al₂O₃ ratios, which approach the shergottite range. Calculated water contents &gt;1.5 wt. % are required to fully match the shergottite range, which is higher than that proposed in previous works. Instead, I propose that a combination of partial source depletion and elevated water contents can fit the observed shergottite compositions with reasonable water contents (∼0.5 wt. % and lower). I also demonstrate that assimilation of a depleted harzburgitic mantle at crust-mantle boundary pressures (∼1 GPa) can elevate magmatic SiO₂ contents to levels seen in the shergottites. Melting of a variably hydrated partially depleted mantle, followed by reaction with a similarly depleted mantle at the crust-mantle boundary is thus demonstrated to be a mechanism that fully fits the chemistry of the shergottites.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 5","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883921","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":"Effect of Solar Wind and Micrometeoroid Impact on the Lunar Water Cycle: A Molecular Dynamics Study","authors":"Anastasis Georgiou,&nbsp;Ziyu Huang,&nbsp;Li Hsia Yeo,&nbsp;William Farrell,&nbsp;Sebastien Verkercke,&nbsp;Jesse R. Lewis,&nbsp;Chuanfei Dong,&nbsp;Liam S. Morrissey","doi":"10.1029/2024JE008687","DOIUrl":"https://doi.org/10.1029/2024JE008687","url":null,"abstract":"<p>We have used molecular dynamics (MD) simulations to better understand the role of solar wind (SW) implanted hydrogen and micrometeoroid impacts on the lunar water cycle. Our simulations consider both the effect of initial hydrogen implantation profile along with the impact characteristics of the micrometeoroid (angle, size). Results show that water formation is strongly influenced by the initial depth location of hydrogen in the lunar soil, along with the impactor's characteristics. When hydrogen is distributed (instead of near surface) we find that nearly all of the water formed after a micrometeoroid impact was retained in the substrate. We also observe an increase in water production when micrometeoroids impact the surface at a normal angle compared to more glancing oblique impacts. In contrast, when micrometeoroids impact the surface of a substrate with near surface hydrogen we observe water loss characteristics and little retention. We also use these models to study the mechanism of water production within the substrate.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143875620","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":"Diagenetic Features Reveal the Influence of the Greenheugh Pediment on the Alteration History of Gale Crater, Mars","authors":"Jordan Ando,&nbsp;Rachel Y. Sheppard,&nbsp;Alexander B. Bryk,&nbsp;Vivian Sun,&nbsp;Christina H. Seeger,&nbsp;Abigail A. Fraeman,&nbsp;Alivia M. Eng,&nbsp;Linda Kah,&nbsp;Amanda N. Rudolph","doi":"10.1029/2024JE008891","DOIUrl":"https://doi.org/10.1029/2024JE008891","url":null,"abstract":"<p>We investigate the nature of diagenetic features encountered by the Curiosity rover within Mount Sharp from sols 1900–3,049. Using Curiosity's Mars Hand Lens Imager and Mast Camera (Mastcam), we classify diagenetic features into established morphological categories and assess their spatial distribution, density, and size. Our analysis reveals variations in diagenetic feature density and morphology linked to stratigraphic boundaries and proximity to the Greenheugh Pediment unconformity, highlighting the role of diagenetic fluids in shaping these features. We find a reduction in diagenetic features at the Jura to Knockfarril Hill member boundary, a spike in feature abundance at the Knockfarril Hill to Glasgow member boundary, and a strong statistical relationship between feature abundance and vertical distance from the Greenheugh Pediment. These trends point to a dynamic history of diagenetic fluid flow, influenced by variations in porosity, permeability, and structural controls, including the presence of the Pediment.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008891","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143871727","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":"Revealing the Moon's Taurus-Littrow Landslide via Integrated Analysis of Pristine Apollo 17 Soil Core 73001/2","authors":"Mason Neuman,&nbsp;Bradley L. Jolliff,&nbsp;Kun Wang,&nbsp;Noah Petro,&nbsp;Jessika Valenciano,&nbsp;Clive R. Neal,&nbsp;Scott Eckley,&nbsp;Jeremy Kent,&nbsp;Lingzhi Sun,&nbsp;Paul Lucey,&nbsp;Samantha Bell,&nbsp;Katherine Helen Joy,&nbsp;Romain Tartese,&nbsp;Rhian Jones,&nbsp;Paul Carpenter,&nbsp;Richard V. Morris,&nbsp;Nikole C. Haney,&nbsp;Steven Simon,&nbsp;Michael Cato,&nbsp;Charles K. Shearer,&nbsp;Kees C. Welten,&nbsp;Kunihiko Nishiizumi,&nbsp;Marc W. Caffee,&nbsp;Roberto A. Colina-Ruiz,&nbsp;Thomas Kroll,&nbsp;Dimosthenis Sokaras,&nbsp;Hope A. Ishii,&nbsp;John P. Bradley,&nbsp;Jeffrey Gillis-Davis,&nbsp;James A. McFadden,&nbsp;Michelle S. Thompson,&nbsp;Roy Christoffersen,&nbsp;Lindsay P. Keller,&nbsp;Justin I. Simon,&nbsp;Francis M. McCubbin,&nbsp;Ryan A. Zeigler,&nbsp;Juliane Gross,&nbsp;Richard A. Ketcham,&nbsp;Romy D. Hanna,&nbsp;David Edey,&nbsp;the ANGSA Science Team","doi":"10.1029/2024JE008556","DOIUrl":"https://doi.org/10.1029/2024JE008556","url":null,"abstract":"<p>The “light mantle” deposit at the base of South Massif in the Moon's Taurus-Littrow Valley was a primary science target for the Apollo 17 exploration. The possibility that it was a landslide triggered by ejecta from Tycho Crater is critical for establishing the age of Tycho and constraining recent lunar impact chronology; however, the mechanism of emplacement of the deposit has recently been questioned. The newly opened 73001/73002 double drive tube from Station 3 sampled 70.6 cm deep into the regolith and represents the first stratigraphic section of an extraterrestrial landslide deposit returned to Earth. Here we provide an overview of the stratigraphy of the 73001/73002 core based on top to bottom variations revealed by coordinated laboratory analyses and explore constraints on the emplacement of the light mantle deposit. Briefly, the upper ∼10 cm of 73002 contains a disturbed zone from space weathering and emplacement of ejecta from a nearby crater that excavated and ejected basaltic material. Below 10 cm is a nearly uniform unit of immature regolith. These data support a single event for the emplacement of the deposit at this location, followed by weathering and mixing of materials from nearby crater ejecta in the upper 10 cm. Slight variations in chemistry and clast components may reflect the relative stratigraphy of the South Massif slope, with material toward the bottom of 73001 originating from lower slopes and material from higher up in the core representing regolith from higher up the South Massif slopes.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008556","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143871729","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 Brac/Dourbes Olivine-Cumulate Rock, Séítah Formation, Jezero Crater Floor, Mars: Its Parent Magma, and Relation to Basalts of the Máaz Formation","authors":"Allan H. Treiman,&nbsp;Juan D. Hernández-Montenegro,&nbsp;Roger C. Wiens,&nbsp;Larry Wade,&nbsp;Scott VanBommel,&nbsp;Jason Van Beek,&nbsp;Arya Udry,&nbsp;Mike M. Tice,&nbsp;Mariek E. Schmidt,&nbsp;Kelsey Moore,&nbsp;Yang Liu,&nbsp;Peter Lawson,&nbsp;Abigail Knight,&nbsp;David Arge Klevang,&nbsp;Tanya Kizovski,&nbsp;Michael M. W. Jones,&nbsp;Joel A. Hurowitz,&nbsp;Robert Hodyss,&nbsp;Jesper Henneke,&nbsp;David Flannery,&nbsp;Robert Denise,&nbsp;Vinciane Debaille,&nbsp;Morgan L. Cable,&nbsp;Adrian Brown,&nbsp;Olivier Beyssac,&nbsp;Paul Asimow,&nbsp;Abigail C. Allwood","doi":"10.1029/2024JE008539","DOIUrl":"https://doi.org/10.1029/2024JE008539","url":null,"abstract":"<p>The Mars 2020 rover, <i>Perseverance</i>, encountered a range of basaltic igneous rocks on the floor of Jezero crater, two of which are olivine cumulates, formed by accumulation of olivine crystals from basaltic magma. These olivine cumulates lie in a geomorphically distinct region, named Séítah, on the Jezero crater floor. To understand the origin of the olivine cumulates and their relationship with the adjacent basalts of the Máaz formation, we calculated the composition of the parent magma of one of the olivine cumulates, named Brac, based on chemical analyses and mineralogic interpretations from the Planetary Instrument for X-ray Lithochemistry (PIXL) instrument. Acceptable Brac/Dourbes parent magmas are olivine tholeiite basalts with SiO₂ ∼ 45%, MgO ∼ 8%, FeO_Tot ∼ 27%, Al₂O₃ ∼ 6%, and total alkali oxides of ∼2.8% weight. These compositions are similar to one of the Máaz basalts, the rock Rimplas, which is stratigraphically close to Séítah, but chemically distinct from other Máaz basalts. Rimplas could (within uncertainty) be a sample of the Brac parent magma, but it is more likely that Rimplas and Brac had a common (or similar) parent magma. Geochemical similarities between Rimplas and the other Máaz basalts thus suggest that Brac (and other olivine-rich rocks of Séítah) and the Máaz basalts could be geochemically related; they could have been cogenetic and possibly contemporaneous, or could have been derived (at different times) from similar or related mantle source(s).</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865667","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":"Origin and Development of Interbedded Clays and Sulfates in Equatorial Layered Deposits of Meridiani Planum, Mars","authors":"B. Baschetti,&nbsp;A. Tullo,&nbsp;M. Massironi,&nbsp;C. Carli,&nbsp;F. Altieri,&nbsp;A. Breda,&nbsp;F. Tateo,&nbsp;R. Pozzobon,&nbsp;M. Baroni","doi":"10.1029/2024JE008564","DOIUrl":"https://doi.org/10.1029/2024JE008564","url":null,"abstract":"<p>Equatorial Layered Deposits (ELDs) are sedimentary landforms found at equatorial latitudes of Mars showing repetitive bedding and commonly associated with hydrous minerals. These deposits are important archives of Mars' past aqueous conditions yet in most cases their formation mechanisms are still debated and elusive. Here we provide a detailed characterization of the mineralogy and stratigraphy of three different exposures of ELDs in Meridiani Planum, where such formations are found within small impact craters and are dated back to the Noachian-Hesperian boundary. Our analysis highlights a varying degree of mixture between polyhydrated Mg sulfates and Fe/Mg phyllosilicates within the beds of all three chosen targets, with several alternating strata of sulfate-rich and phyllosilicate-rich materials. In one case, Al-phyllosilicates are also found along with their Fe/Mg counterpart. This is a much more varied mineral assemblage than previously reported for ELDs in this area. We propose a formation mechanism which explains the observed interbedding as a result of surface ponding of groundwaters, aqueous alteration of atmospherically-sourced basaltic materials and water table/pH oscillations (wet/dry cycles) leading to recurrent sulfate precipitation. Our findings show how local environments play a substantial role in recording small-scale variations of complex aqueous processes, generally not observed at regional and global scales on Mars.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008564","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865668","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":"Magnetization of Iron Meteorites up to the Meter in Size as Possible Analogs for Asteroid Psyche","authors":"Clara Maurel,&nbsp;Elise Clavé,&nbsp;Jérôme Gattacecca,&nbsp;Minoru Uehara,&nbsp;Elias N. Mansbach,&nbsp;Timothy J. McCoy,&nbsp;Benjamin P. Weiss","doi":"10.1029/2024JE008810","DOIUrl":"https://doi.org/10.1029/2024JE008810","url":null,"abstract":"<p>Meteorite paleomagnetic studies indicate planetesimal generated magnetic fields, but spacecraft magnetic measurements have yet to identify asteroidal natural remanent magnetization (NRM). This apparent discrepancy is of particular interest in the context of the NASA Psyche mission, which will search for evidence of past magnetic activity of the metal-rich asteroid (16) Psyche. Here, we aim to test whether the NRM of meteorites inevitably drops below detectable values as specimen size increases, which could explain why asteroidal NRMs could never be detected. We focus on iron meteorites as possible analogs to (16) Psyche's constituent material. To do so, we measure the remanent magnetic field and estimate the NRM of samples of four iron meteorites with volumes between mm³ and m³. We find that their estimated NRMs decrease with increasing sample size but appear to plateau. These data are compatible with the idea that the bulk NRM of increasingly large objects becomes dominated by the fraction of this NRM produced by assemblages of magnetic minerals sharing a common magnetization direction. Moreover, all m³-sized meteorites carry NRMs that are two orders of magnitude above the detectability limit of the Psyche Magnetometer, three of which are possibly pre-terrestrial. These data, acquired on some of the largest masses of iron meteorites available on Earth, support the range of plausible NRM values for km-size regions of (16) Psyche, used to establish the spacecraft Magnetometer's performance requirements. Nevertheless, large-scale events such as brecciation of the asteroid following magnetization acquisition could always lower the asteroid's NRM below the detectability limit.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008810","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143861718","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":"Unveiling What Makes Saturn Ring: Quantifying the Amplitudes of Saturn's Planetary Normal-Mode Oscillations and Trends in C-Ring Properties Using Kronoseismology (VII)","authors":"V. M. Afigbo,&nbsp;M. M. Hedman,&nbsp;P. D. Nicholson,&nbsp;R. G. French,&nbsp;C. R. Mankovich,&nbsp;R. G. Jerousek,&nbsp;J. Dewberry","doi":"10.1029/2024JE008710","DOIUrl":"https://doi.org/10.1029/2024JE008710","url":null,"abstract":"<p>Certain spiral density waves in Saturn's rings are generated through resonances with planetary normal modes, making them valuable probes of Saturn's internal structure. Previous research has primarily focused on the rotation rates of these waves. However, other characteristics of these waves also contain valuable information about the planet's interior. In this work, we investigate the amplitudes of the waves across the C-ring by analyzing high signal-to-noise profiles derived from phase-corrected averages of occultation profiles obtained by Cassini's Visual and Infrared Mapping Spectrometer (VIMS). By fitting these wave profiles to linear density wave models, we estimate the ring's surface mass density, mass extinction coefficient, and effective kinematic viscosity at 34 locations in the C-ring, as well as the amplitude of the gravitational potential perturbations associated with 6 satellite resonances and 28 planetary normal mode resonances. Our estimates of the C-ring's mass extinction coefficient indicate that the typical particle mass density is around 0.3 g/cm³ interior to 84,000 km, but can get as low as 0.03 g/cm³ exterior to 84,000 km. We also find the ring's viscosity is reduced in the outer C-ring, which is consistent with the exceptionally high porosity of the particles in this region. Meanwhile, we find the amplitudes of Saturn's normal modes are complex functions of frequency, <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <mi>ℓ</mi>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> $ell $</annotation>\u0000 </semantics></math> and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <mi>m</mi>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> $m$</annotation>\u0000 </semantics></math>, implying that multiple factors influence how efficiently these modes are excited. This analysis identified two primary sources of these normal-mode oscillations: a deep source located close to Saturn's core, and a shallow source residing near the surface.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008710","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143861719","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}