IcarusPub Date : 2026-02-01Epub Date: 2025-11-05DOI: 10.1016/j.icarus.2025.116871
R. Keerthana , R. Annadurai , K.N. Kusuma
{"title":"Morphological, mineralogical, and chronological mapping of Briggs floor fractured crater using lunar remote sensing datasets","authors":"R. Keerthana , R. Annadurai , K.N. Kusuma","doi":"10.1016/j.icarus.2025.116871","DOIUrl":"10.1016/j.icarus.2025.116871","url":null,"abstract":"<div><div>This study investigates the morphology, mineralogy, and chronology of the Briggs crater (37 km diameter), situated west of the Oceanus Procellarum, employing high-resolution data from recent lunar missions. Lunar Reconnaissance Orbiter (LRO) images, Terrain Mapping Camera (TMC) Ortho images, and Digital Elevation Models (DEMs) from both the Chandrayaan-2 and Kaguya were employed to study the morphology of the crater. The morphological investigation identified distinct features in Briggs Crater, including a well-preserved crater rim, terraced walls, a convex floor indicative of subsurface uplift, an uplifted central peak, mounds, and prominent NE-SW and N-S trending concentric and radial fractures. Additionally, a fresh impact crater and localized slumping along the crater walls suggest ongoing surface modifications. Briggs Crater exhibits characteristics of a Class-2 Floor-Fractured Crater (FFC), including an uplifted floor and prominent concentric fractures, consistent with previously established classifications. The presence of radial and concentric fractures on the Briggs Crater floor suggests a combination of brittle and ductile deformation. Variations in fracture dimensions indicate differential stress distribution during floor uplift, likely influenced by subsurface magmatic intrusion or impact-induced processes. Integrated Band Depth (IBD) and Mineral indices-based color composite images were generated using M<sup>3</sup> datasets to better understand mineralogy. These images enable the extraction of spectral signatures for mineralogical investigation and highlight the diversity of lithological composition. Spectral absorption analysis, IBD mapping, and mineral indices collectively confirm that the central peak exposes fresh High-Calcium Pyroxene (HCP) from deeper crustal levels, while the floor, rim, wall, and ejecta show weaker, mixed, and weathered pyroxene signatures. Integrating morphology and mineralogy with Crater Size-Frequency Distributions (CSFD)-based chronology, it has been suggested that Briggs Crater formed during the late Imbrian period (3.6 Ga). The N-S trending concentric fractures on the Briggs crater floor likely represent tectonic or magmatic activity that occurred between ∼310 Ma and ∼ 270 Ma during the Eratosthenian period, significantly after the initial crater formation.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116871"},"PeriodicalIF":3.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IcarusPub Date : 2026-02-01Epub Date: 2025-10-03DOI: 10.1016/j.icarus.2025.116831
E. Piacenti , A.J. Dombard
{"title":"Predictive modeling of gravitational anomalies for geological features along Europa's seafloor, utilizing line-of-sight Doppler residuals","authors":"E. Piacenti , A.J. Dombard","doi":"10.1016/j.icarus.2025.116831","DOIUrl":"10.1016/j.icarus.2025.116831","url":null,"abstract":"<div><div>Exploring Europa, one of Jupiter's icy moons, is crucial for advancing our understanding of extraterrestrial geology and potential habitability. At present, study of gravity anomalies represents the best way to interrogate Europa's seafloor; however, current and expected global gravity models are insufficient for detecting and characterizing specific geologic features due to their coarse resolution. This study aims to determine whether Line-of-Sight (LoS) gravity signatures derived from Doppler residuals can be used to identify specific geological features on Europa's seafloor, such as mountain ranges, valleys, impact basins, rift zones, and subduction zones. Here, we assess the detectability of these features and evaluate whether the resolution from Europa Clipper would be sufficient to distinguish them. Our findings indicate that the expected LoS Doppler residual data likely will not provide sufficient resolution to differentiate between various geological formations on Europa's seafloor, primarily due to the spatial scale of the expected features compared to the spacecraft's distance from the surface. These limitations suggest that gravity signatures alone may not offer enough information for the interpretation of Europa's seafloor geology.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116831"},"PeriodicalIF":3.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IcarusPub Date : 2026-02-01Epub Date: 2025-10-08DOI: 10.1016/j.icarus.2025.116844
B.G. Rider-Stokes , A.Y.C. Wong , T.H. Burbine , E. MacLennan , R.C. Greenwood , S.L. Jackson , M. Anand , L.F. White , M.M. Grady
{"title":"The Noritic mineralogy of V- and S-type objects and the links with asteroid (4) Vesta","authors":"B.G. Rider-Stokes , A.Y.C. Wong , T.H. Burbine , E. MacLennan , R.C. Greenwood , S.L. Jackson , M. Anand , L.F. White , M.M. Grady","doi":"10.1016/j.icarus.2025.116844","DOIUrl":"10.1016/j.icarus.2025.116844","url":null,"abstract":"<div><div>Ungrouped achondrites with affinities to Howardite-Eucrite-Diogenite (HED) meteorites offer critical insights into the diversity of differentiated bodies in the inner Solar System. They can help address the longstanding discrepancy between V-type asteroids related to the asteroid (4) Vesta and those that show similar characteristics but lack a dynamical relationship. In this study, we present new spectral, mineralogical, and oxygen isotopic analyses of two ungrouped achondritic meteorites. Al Bir Lahlou 001 exhibits strong compositional and spectral similarities to typical V-type asteroids, while Wan Zawatin 001 shows unexpected affinities to S-type asteroids. These findings suggest a more complex evolutionary history for differentiated asteroids than previously recognized and support the existence of multiple asteroidal bodies with HED-like characteristics. Our results highlight the importance of continued investigation into ungrouped achondrites to better understand the formation, distribution, and evolution of differentiated material beyond the Vesta family.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116844"},"PeriodicalIF":3.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Zonal-flow variability associated with meridional circulation at the cloud top in a Venus atmospheric general circulation model","authors":"Masaru Yamamoto , Kohei Ikeda , Masaaki Takahashi , Masaki Satoh","doi":"10.1016/j.icarus.2025.116860","DOIUrl":"10.1016/j.icarus.2025.116860","url":null,"abstract":"<div><div>Internal variability of cloud-top super-rotation with periods of about a Venus day is found in a Venus AORI (Atmosphere and Ocean Research Institute, The University of Tokyo) GCM (General Circulation Model), along with diurnal variations of the meridional circulation and long-wave radiative cooling. In the diurnal cycle of the cloud-top zonal flow, the high-latitude jets increase, while the meridional circulation enhances the poleward momentum flux. Subsequently, the equatorial super-rotation becomes its maximum after the high-latitude jets reach their maximum. The present study reveals the formation of the diurnal cycle of the zonal flow by the meridional circulation and the destruction of the diurnal cycle by the amplified Eliassen-Palm (EP) flux in the model. Although the variability of the meridional circulation is stably diurnal throughout the simulation, the periodicity of the EP flux is not always diurnal. The diurnal cycle of the zonal flow becomes weak and the periodicities of ∼two Venus days appear in the model, when the zonal-flow acceleration by the EP flux is stronger than that by the meridional circulation at the equator and at the high-latitude jet cores. Moreover, when cyclic data gaps of cloud-tracking observation are considered in this study, the diurnal cycle of the zonal flow is unclear, and the peak-to-peak intervals of the zonal-wind maxima appear to be ∼two Venus days.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116860"},"PeriodicalIF":3.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IcarusPub Date : 2026-02-01Epub Date: 2025-11-01DOI: 10.1016/j.icarus.2025.116865
Filip Matuszewski , Véronique Vuitton , Julia Shouse , Thibault Launois , Naïla Chaouche-Mechidal , Elsa Hénault , Laurène Flandinet , Èric Quirico , Rosario Brunetto , Philippe Boduch , Alicja Domaracka , Hermann Rothard , Fabien Stalport , Francois Regis Orthous Daunay , Hervé Cottin , Sarah Hörst , Roland Thissen
{"title":"Ion induced formation of complex organic nitrogen molecules in solid-phase adenine","authors":"Filip Matuszewski , Véronique Vuitton , Julia Shouse , Thibault Launois , Naïla Chaouche-Mechidal , Elsa Hénault , Laurène Flandinet , Èric Quirico , Rosario Brunetto , Philippe Boduch , Alicja Domaracka , Hermann Rothard , Fabien Stalport , Francois Regis Orthous Daunay , Hervé Cottin , Sarah Hörst , Roland Thissen","doi":"10.1016/j.icarus.2025.116865","DOIUrl":"10.1016/j.icarus.2025.116865","url":null,"abstract":"<div><div>Complex organic molecules have been found in many space environments like meteorites and comets. There, they are subjected to various forms of radiation (photons, electrons, ions), opening the question of their behavior and chemical evolution, which may have played a crucial role in chemical processes of astrobiological interest. In this study, we investigate the irradiation of adenine (C<span><math><msub><mrow></mrow><mrow><mn>5</mn></mrow></msub></math></span>H<span><math><msub><mrow></mrow><mrow><mn>5</mn></mrow></msub></math></span>N<span><math><msub><mrow></mrow><mrow><mn>5</mn></mrow></msub></math></span>) with oxygen and neon ions. The free parameters of the experiments include varying energies (30-70 keV), temperatures (150, 300 K), sample thicknesses (138-554 nm), and ion fluences (0.69-5 <span><math><mo>×</mo></math></span> 10<span><math><msup><mrow></mrow><mrow><mn>15</mn></mrow></msup></math></span> ions cm<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup></math></span>). In situ IR spectroscopy reveals the appearance of C<span><math><mo>≡</mo></math></span>N and N=C=N bands indicating the formation of new species. Ex situ ultra-high-resolution mass spectrometry shows the formation of new complex organic molecules that far exceed the molecular mass of adenine. These macromolecules show great chemical diversity and can be expressed as (HCN)<span><math><msub><mrow></mrow><mrow><mi>z</mi></mrow></msub></math></span>R families, where z can reach 14 and R can be C<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span>, H<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span>, N<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span>, N<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span>H<span><math><msub><mrow></mrow><mrow><mi>y</mi></mrow></msub></math></span>, C<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span>H<span><math><msub><mrow></mrow><mrow><mi>y</mi></mrow></msub></math></span> or C<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span>N<span><math><msub><mrow></mrow><mrow><mi>y</mi></mrow></msub></math></span>. In total, nearly 100 individual families have been identified, 28 of which can be found in every irradiated sample. Their aromaticity equivalent is higher than that in other N-rich samples such as Titan tholins and HCN-polymers, corresponding to polycyclic aromatic nitrogen-bearing hydrocarbons. The high amount of nitrogen in these molecules indicates a very efficient incorporation of nitrogen in the solid phase during the irradiation of adenine. The ease with which complex organic matter forms through irradiation highlights the relevance of these species in space environments.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116865"},"PeriodicalIF":3.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145462600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IcarusPub Date : 2026-02-01Epub Date: 2025-09-26DOI: 10.1016/j.icarus.2025.116835
L. Miché Aaron-Hennig , Kim Seelos
{"title":"Investigating the formation of impact-exhumed hydrated sulfates in Tyrrhena Terra, Mars","authors":"L. Miché Aaron-Hennig , Kim Seelos","doi":"10.1016/j.icarus.2025.116835","DOIUrl":"10.1016/j.icarus.2025.116835","url":null,"abstract":"<div><div>Understanding the distribution and provenance of hydrated minerals within Noachian terrains is essential to deciphering Mars' crustal formation and alteration history. The phyllosilicate and carbonate minerals typically found within Noachian geologic units, for instance, have been attributed to a warmer, wetter climate that preceded a transition to the sulfate-dominated, colder, drier, and more acidic conditions in the Hesperian and Amazonian. However, these broad associations may not hold true locally. In Tyrrhena Terra, the heart of the Noachian-aged cratered highlands, three isolated craters host an unusual occurrence of hydrated sulfates alongside a variety of other alteration minerals more typically associated with the Noachian era. This paper investigates the presence of these outcrops in order to understand their origin, relationship to these co-located minerals, and implications for aqueous history and crustal evolution of Mars. Using Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) data along with other contextual remote sensing data, we present a mineralogical mapping and spectral analysis of primary and secondary minerals at each location where sulfates are observed. Based on our characterization, we have constrained the formation of the sulfates to be associated with epithermal alteration or sulfide oxidation rather than impact or mechanically induced alteration. This suggests a complex sequence of aqueous alteration, potentially involving one or more steps, which we intend to explore further in future studies. The discovery of these sulfate minerals within predominantly phyllosilicate and carbonate territories challenges the conventional timeline of Mars' climate evolution, hinting that transitions between climatic epochs may have overlapped or been more regionally varied than previously thought.</div></div><div><h3>Plain language summary</h3><div>This research looks at how certain minerals, called hydrated sulfates, formed on Mars and what they can tell us about the planet's history. Sulfate outcrops were found in a region called Tyrrhena Terra, which is very old and dates back to a time when Mars was warmer and wetter than it is now. By studying data from a special camera on a Mars orbiter, we find that these minerals were brought to the surface by meteor impacts. They were likely formed a long time ago, before the impacts happened. This research explores different ways these minerals could have formed. One idea is that they were created by hot water moving through the ground, while another suggests they formed from chemical reactions involving sulfides (another type of mineral). The findings suggest that Mars' crust in this area was not necessarily uniform but could have had patches of different materials. These patches were altered by water, leading to the formation of the sulfates we see today. Understanding these minerals helps scientists learn more about the ancient climate and water activity on Mars. It ","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116835"},"PeriodicalIF":3.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145358802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Probing the geological setting of exoplanets through atmospheric analysis: Using Mars as a test case","authors":"Monica Rainer , Evandro Balbi , Francesco Borsa , Paola Cianfarra , Avet Harutyunyan , Silvano Tosi","doi":"10.1016/j.icarus.2025.116847","DOIUrl":"10.1016/j.icarus.2025.116847","url":null,"abstract":"<div><div>One of the frontier research fields of exoplanetary science is the study of the composition and variability of exoplanetary atmospheres. This field is now moving from the gas giant planets towards the smaller and colder telluric planets, and future instruments like ANDES will focus on the observations of the atmosphere of telluric planets in the habitable zone in reflected light. These future observations will possibly find variable signals due to the view of different hemispheres of the planet. Particularly, the strength of the signal may be linked to the thickness of the atmospheric layer probed, and therefore to the average altitude variations of the planetary surface, that are related to the global geodynamic evolution of the planet. To better prepare for the interpretation and exploitation of these future data, we used Mars as a Solar System analog of a spatially resolved telluric exoplanet. We observed the reflected light of Mars with the high-resolution near-infrared (NIR) spectrograph GIANO-B (widely used in exoplanetary atmospheric studies) during a 3 month period: we studied the spatial and temporal variations of the Martian CO<sub>2</sub> signal using the least-squared deconvolution technique (LSD), to mimic as closely as possible the standard exoplanetary atmospheric analysis. We linked the variations found to the well-known Martian geological surface characteristics: we found a clear dependence of the strength of the CO<sub>2</sub> signal with the thickness of the Martian atmospheric layer by comparing the retrieved CO<sub>2</sub> signal with the altitudes of our pointings. The proposed strategy is promising: it proved to be effective on Mars and may shed light on the variations in the strength of atmospheric signal of telluric exoplanets.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116847"},"PeriodicalIF":3.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Visible-near infrared spectral behavior of Mars-analog clays, sulfate, and basalt mixtures","authors":"Beatrice Baschetti , Cristian Carli , Matteo Massironi , Fabio Tateo , Giulia Alemanno","doi":"10.1016/j.icarus.2025.116846","DOIUrl":"10.1016/j.icarus.2025.116846","url":null,"abstract":"<div><div>Understanding Mars’ past environmental and climate characteristics greatly relies on the orbital detection of the numerous hydrous minerals present on the planet’s surface. These include clay minerals and sulfates, especially when they are found in close proximity to each other. However, remote sensing observations pose several challenges and limits to quantitative mineral observations. In addition, these minerals are often likely mixed with basaltic regolith originating from the planet’s volcanic crust, which affects their spectral signature. In this framework, measurements on analogs in a controlled laboratory environment are essential support to remote sensing data to perform quantitative spectral analysis. We conduct visible and near-infrared reflectance spectroscopy on binary and ternary intimate mixtures among (a) basalt, (b) Fe/Mg-clay minerals (nontronite, saponite), and (c) polyhydrated sulfate (hexahydrite) powders. Binary mixtures include combinations of (a)-(b) and (a)-(c), while ternary mixtures combine all three: (a)-(b)-(c). Absorption feature variations are assessed with measurements of band center, band area, and band depth. The results of binary mixtures indicate that basalt does not generally interfere with the position of diagnostic OH- and H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O absorption features in the selected clays and sulfate samples but systematically reduces their band depth/area, leading to a possible underestimating of the hydrous component. Ternary mixing experiments highlight a strong and complex interaction between clay and sulfate endmembers, with variation in relative abundance causing the minima of their <span><math><mrow><mn>1</mn><mo>.</mo><mn>4</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> and <span><math><mrow><mn>1</mn><mo>.</mo><mn>9</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> OH- and H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O absorption features to shift. Such shifts are significantly larger than the possible basalt-induced effect and show a step-like behavior, with minimum values clustering between two groups separated by <span><math><mo>≥</mo></math></span> 30 nm. The gap typically corresponds to 1:2 clay-to-sulfate ratio. This characteristic places important constraints on the relative abundance of clays and sulfates in mixed settings, independently of the basalt abundance. The results presented here provide substantial support in studying orbital detections of mixed clay/sulfate signatures. Moreover, they offer a more realistic interpretation framework in which the effects of Mars-like basaltic regolith are directly assessed.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116846"},"PeriodicalIF":3.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IcarusPub Date : 2026-02-01Epub Date: 2025-10-19DOI: 10.1016/j.icarus.2025.116857
A.G. Nair , I.B. Smith
{"title":"Scalloped cliff formations of north polar layered deposits of mars: A new catalog","authors":"A.G. Nair , I.B. Smith","doi":"10.1016/j.icarus.2025.116857","DOIUrl":"10.1016/j.icarus.2025.116857","url":null,"abstract":"<div><div>The north polar layered deposits of Mars are composed mainly of water ice with varying fractions of dust in the layers. This almost 2-km stack records a history of accumulation and ablation that tells of climatic episodes. The layers are frequently exposed as outcrops at spiral troughs that can be inspected for geomorphological details related to deposition and ablation cycles. Here, we identify and catalog the 226 morphologic features we call “scalloped cliffs” that exhibit tell-tale signs of variable resistance to erosion in sequential layers. The spatial distribution of scalloped cliffs suggests that they are primarily near the margins on the NPLD, especially in the Gemini Scopuli region of Planum Boreum. Many are immediately associated with an unconformity, providing clues to their origin. Additionally, we present two distinct hypotheses behind their formation that relate to alternating layer properties, especially related to dust content and susceptibility to ablation. For each example, we hypothesize that the scalloped cliffs form when friable dust-rich lag deposits, at unconformities, are emplaced between more resistant icy layers and that their unique wavy appearance is due to oblique wind scouring.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116857"},"PeriodicalIF":3.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IcarusPub Date : 2026-02-01Epub Date: 2025-10-17DOI: 10.1016/j.icarus.2025.116856
Juulia-Gabrielle Moreau , Argo Jõeleht , Anna Losiak , Meng-Hua Zhu , Jüri Plado
{"title":"Water saturation in texturally porous carbonate rocks: Shock thermodynamics and dampening of the shock","authors":"Juulia-Gabrielle Moreau , Argo Jõeleht , Anna Losiak , Meng-Hua Zhu , Jüri Plado","doi":"10.1016/j.icarus.2025.116856","DOIUrl":"10.1016/j.icarus.2025.116856","url":null,"abstract":"<div><div>Sedimentary rocks often form the upper layers or the entire target rocks in impact events. Thermodynamic properties of sedimentary rocks related to porosity and water saturation affect the process of impact crater formation. The heterogeneous distribution of sedimentary facies can complicate the development and distribution of shock effects, especially in numerical modeling. This work focuses on the shock thermodynamic properties of carbonate rocks with differing porosity textures (e.g., isolated pores, interstitial porosity, elongated pores) and water saturation levels. Using mesoscale numerical modeling, we found that water saturation reduces shock temperatures compared to those in dry, porous carbonate rocks. The orientation of elongated pores and porosity lineations influences the shock temperature distribution and rock deformation at angles of 50–90° to the shock front. Additionally, due to complex shock wave interactions, interstitial porosity is key in creating temperature zonations around larger grains.</div></div>","PeriodicalId":13199,"journal":{"name":"Icarus","volume":"445 ","pages":"Article 116856"},"PeriodicalIF":3.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145358789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}