The radiometric ages of the returned samples are the cornerstone of lunar cratering chronology models. However, all the previous samples were from the lunar nearside and the radiometric ages of those samples that can be associated with particular surfaces are <4.0 billion years. On 25 June 2024, Chang'e-6 successfully returned 1.935-kilogram samples from the lunar farside. The samples included local basalts with an age of 2807 ± 3 million years and the norites with an age of 4247 ± 5 million years likely corresponding to the age of the South Pole-Aitken basin. With these radiometric ages, we refined the lunar chronology function (CF) and verified that it is still consistent with a combination of an exponential decrease and a linear rate. We further derived the impacting rate and found it supports a smooth decay instead of abrupt changes of the impactor flux at early times. The refined lunar CF can be used to obtain more reliable ages for unsampled lunar areas and provide critical constraint for the lunar early impact history.

A new Morphological Catalog of Mercury’s Craters was created at the Sternberg State Astronomical Institute, Moscow State University, together with the Moscow State University of Geodesy and Cartography based on data from the MESSENGER spacecraft. This catalog includes information on the coordinates, diameters, and morphology of 12 365 craters with diameters ≥10 km. The catalog was created using data from the Mercury Crater Catalog, prepared at Brown University (United States), and a global mosaic of Mercury surface images based on data from the MESSENGER spacecraft. Analysis of the new Morphological Catalog has shown that most Mercury craters with a diameter of ≥10 km have a smoothed or partially destroyed rim and a flat floor. The article provides a detailed description of the morphological features of Mercury’s craters. Table 1 shows the percentage of craters with certain features on Mercury and the Moon. It turned out that there are significantly more well-preserved craters on the Moon than on Mercury. Most of Mercury’s craters have terraces and collapses on their inner slopes (65

Chang'e-6 is the first sample-return mission from the lunar farside and has returned samples from the landing site within the Apollo basin on June 25, 2024. Lobate scarps have been identified approximately 300 km northwest of the Chang'e-6 landing site (and at western rim of the Apollo basin). The distribution and morphological characteristics of lobate scarps are crucial for understanding the lunar geological history of the landing area. In this research, we have analyzed the spatial distribution and formation age of lobate scarps at western rim of the Apollo basin. The morphology, dynamical models, and formation ages of lobate scarps are investigated through Mohr-Coulomb measurement and crater size-frequency distribution measurements (CSFD). We generated highresolution digital elevation models by deep learning method using Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera (NAC) imagery and Selenological and Engineering Explorer (SELENE) and Lunar Orbiter Laser Altimeter (LOLA) Digital Elevation Model (SLDEM), which enabled the study of lobate scarps in areas lacking NAC DTM coverage, and their accuracy were thoroughly validated. The displacement-length ratios of the lobate scarps are calculated, with an average of approximately 3.80 %. By calculating the morphological parameters of lobate scarps, inferring their formation ages, and studying their spatial distribution, we find that these lobate scarps are distributed in the highlands nearby the Apollo basin edge. They were formed under horizontal compressive stresses exceeding 400 MPa during the last 80 Ma, which is consistent with the initially totally molten (ITM) model. This finding is further supported by cross-validation with the 238U/204Pb ratios from lunar far-side samples by the Chang'e-6 mission, challenging the notion that the lunar magma ocean (LMO) can prolong magmatic activity through KREEP.

The Martian isochrons are the basis in analyzing the impact flux and surface dating, and currently, they are usually derived from those of the Moon because no samples have been collected from Mars. However, the isochrons obtained by this method have substantial uncertainty, and they urgently need to be optimized based on the samples that are about to be obtained. To support the upcoming Mars sample return missions, we utilized a high-resolution Context Camera mosaic and selected 17 regions from diverse geological units and ages across Mars’s surface to establish an observed Martian crater production function (PF). Craters were manually mapped across these regions. The crater size–frequency distributions (CSFDs) from these regions have a strong correlation at the same diameter range on a logarithmic scale, indicating that they share a similar distribution shape regardless of geological units and ages. We obtained 155 effective CSFD bins suitable for fitting the crater PF. After testing on different fitting functions, we finally obtained the crater PF for the Martian surface over the diameter range of 0.15 to 13.5 km. There were significant differences between the directly mapped Mars crater PF and those derived from lunar models. In addition, the CSFDs obtained by previous researchers when doing dating works on the Martian surface are more consistent with the newly established crater PF than with the earlier proposed PFs. With the radiometric ages of the samples returned by future Mars sample return missions, this research could become the basis for establishing a new chronology system for Mars.

The ever-changing transparency of the Martian atmosphere hinders the determination of absolute surface colour from spacecraft images. While individual high-resolution images from low orbit reveal numerous colour details of the geology, the colour variation between images caused by scattering off atmospheric dust can easily be of greater magnitude. The construction of contiguous large-scale mosaics has thus required a strategy to suppress the influence of scattering, often a form of high-pass filtering, which limits their ability to convey colour variation information over distances greater than the dimensions of single images. Here we use a dedicated high altitude observation campaign with the Mars Express High Resolution Stereo Camera (HRSC) (Neukum and Jaumann, 2004; Jaumann et al., 2007), applying a novel iterative method to construct a globally self-consistent colour model. We apply the model to colour-reference a high-altitude mosaic incorporating long-range colour variation information. Using only the relative colour information internal to individual images, the influence of absolute image to image colour changes caused by scattering is minimised, while the model enables colour variations across image boundaries to be self-consistently reconstructed. The resulting mosaic shows a level of colour detail comparable to single images, while maintaining continuity of colour features over much greater distances, thereby increasing the utility of HRSC colour images in the tracing and analysis of martian surface structures.

The Chang'e-6 lunar spacecraft returned samples from the southern mare of the Apollo basin. This work analyses the likelihood that a set of six close crater dating measurements of sub-units near the sampling site actually represent a single formation event. Using theoretical considerations, we find that the measurements are consistent with a simultaneous formation hypothesis with about 1 in 6 likelihood, so that a close sequential formation is more probable. Results of radioisotope dating of basaltic fragments from the surface scoop sample were recently reported close to 2.8 Ga. Our crater dating of the vicinity suggests that the upper 2-17 m predominantly records an age of mu 1.66+0.053 population reset of the surface.

We conducted a detailed study using multi-source data to date the mare activity and lobate scarp formation within the Jules Verne crater on the Moon. In previous studies, the Jules Verne crater has been classified as a pre-Nectarian impact crater. Our analysis indicates that it has an absolute model age (AMA) of 4.21−0.034+0.032 Ga. After its formation, a magmatic intrusion event created floor fractures, followed by two basaltic eruption events—one at 3.4 Ga and another at 2.6 Ga. Subsequently, around 1.4 billion years ago, lunar seismic activity likely took place in this region, resetting the surface ages of the crater floor fractures and surrounding areas, as evidenced by the scarp.

Crater size-frequency distribution (CSFD) measurements provide a valuable tool for dating surfaces on terrestrial planetary bodies. In order to derive an age from CSFD measurements, a production function (PF) is required to reflect the size-frequency distribution of craters being formed. However, the most commonly used PFs are only valid to crater diameters up to 300 km. An expansion of the PFs would be beneficial to improve the understanding of the early bombardment history of the Moon. However, there are two main issues affecting the interpretation of the CSFDs of large and multi-ring basins: the determination of a standard main basin rim for multi-ring basins and the low number of large basins. Previously, numerous attempts have been made to define the representative diameters for (multi-ring) basins, which appear in many lunar catalogs. The comparison of four such lunar crater catalogs revealed significant differences in defining basin boundaries and diameters. Therefore, we created a new crater catalog for lunar craters larger than 100 km based on topographic and gravity data and using a consistent definition for basin diameters. We found that on the highlands, the CSFD measurement has not reached equilibrium. Given that the number of empirically measured basins is limited, this investigation naturally must deal with low-number statistics. However, the available data for basins >300 km still allow an empirical analysis to provide insights into this poorly understood part of the lunar PF. We find that the shape of the CSFD is consistent with the impactor size-frequency distribution (SFD) of the Main Asteroid Belt, suggesting an origin from the Main Asteroid Belt. The presence of an additional impactor population cannot be observed in our data, although we cannot exclude the possibility of a second population with a similar SFD. Using the highland CSFD measurement as a reference, we found interesting large discrepancies between the measured and the calculated number of craters and basins on the lunar mare. For instance, we measured 30 craters and basins >= 100 km on mare, but expected 79 using the PF of Neukum et al. (2001). In addition, we identified 9 basins >= 300 km on mare areas, but expected only 5 basins when applying the PF of Neukum et al. (2001).

The evolution of the Moon is driven by both endogenic (e.g., magmatism) and exogenic processes (e.g., impact). The lunar surface can be divided into 3 first-order tectonic units based on differences in geochemistry, crustal thickness, topography, and distribution of structures. However, the interpreted boundaries demarcated by different features varied widely. As research progresses, the understanding of the lunar structure is continuously improving, and new types of structures are constantly being discovered. The previous structural classification system needs to be updated. According to the major geological events and dynamic evolution, the evolutionary history of the Moon can be divided into 3 stages and 1 pivotal event. The first stage (4.52 to 4.3 Ga) is the evolution of the magmatic ocean, and it was dominated by endogenic processes. The formation of South Pole-Aitken (SPA) basin (~4.3 Ga) is the pivotal event of crustal evolution and indicates that the lunar crust had cooled and consolidated to sufficient rigidity to preserve structures. Both endogenic and exogenic processes were active in the second stage (4.3 to 3.0 Ga), which results in numerous impact basins, mare basalt flooding, and different types of associated structures. The last stage (3.0 Ga to the present) is late neotectonic activity, which has weak modification of the tectonic framework. Response of tectonic framework and structure to lunar major geological events had been organized and discussed in this paper, and key scientific issues are summarized. This study can provide reference and support for implementation of subsequent lunar exploration projects.

The samples from lunar farside have great significance for the study of the Moon, and even the solar system. Chang’e-6 landed successfully on the southern mare of the Apollo basin and returned ~2 kg of samples from lunar farside. To provide a better understanding for the background of the returned samples, we conducted detailed crater size-frequency distribution (CSFD) measurements in the Chang’e-6 landing region, the southern mare of the Apollo basin. The southern mare is divided into the western mare (W region) and the eastern mare (E region), and then subdivided into five subunits (W1, W2, W3, W4, W5) and three units (E1, E2, E3), respectively, according to the elevation, TiO2, and FeO abundances. Within the W2 and W5 region, more detailed subunits were separated out. The results show that the southern mare surface was active during two epochs, the Imbrian period and the Eratosthenian period. The basalt eruption lasted for ~1.7 Ga, from 3.28 Ga of the eastern mare to 1.54 Ga of the western mare. The W region is younger than the E region, while the three units of the E region have an age of ~3.2 Ga. The ages of the western mare basalts range from 2.98 Ga to 1.54 Ga, lasting for 1.4 Ga. It is worth noting that the age of the basalt at the Chang’e-6 sampling site is ~1.68 Ga, indicating the samples returned may include components with this very young age.

Introduction:Current efforts for image mosaics from the High Resolution Stereo Camera (HRSC, Jaumann, 2007) on board Mars Express are ongoing (Michael et al. 2016, Michael et al., 2019). Usually, illumination effects between adjacent single images related to the planetary curvature are reduced by using a Lambert correction and subsequent normalization to a common brightness reference. Here we present an extended correction of topography-induced shading effects by using the illumination angles with reference to the local topography represented by the digital terrain model (DTM) associated to every single HRSC scene, resulting in top-of-the-atmosphere albedo images of the surface.Scattering models:When used for illumination corrections taking the local topography into account, the Lambertian model and its associated cosine correction tends to over-correct on large incidence angles (under-illuminated pixels), as observed on crater slopes at low Sun angles. Therefore we do not consider it for our work but use it as a reference for comparison reasons (see Fig. 1 top -- the saturation level of one is reached at around 70° effective incidence angle).The one-parameter model by Minnaert (Minnaert, 1941) is known for its good reproduction of the Martian surface. Depending on its power-law parameter k, the saturation effect of the correction appears at very high incidence angles only and is therefore better suited for topographic corrections. Still, in the case of HRSC, the Sun incidence angle on the ellipsoid is often higher than 60° and adding the slope angles results in incidence angles higher than 80°. This leads to very bright over-corrected pixels in highly inclined areas facing away from the Sun (see Fig. 1 middle -- depending on the k parameter, the saturation level is reached at around 80° incidence).The correction used by Teillet et al. (1982) is well suited for topographic corrections due to its minimal amount of overcorrection (cf. Fig. 1 bottom for plots of varying parameter settings and Fig. 2 for the result). The single parameter is derived by a relation of the incidence on the ellipsoid to the mean incidince with regards to the topography. Figure 1: Correction curves using different photometric functions; top: Lambert model; middle: Minnaert model, emission angle=0°; bottom: Teillet model, incidence on ellipsoid=60°. A reflectance of 0.3 is assumed for all plots.Results:We corrected a common set of HRSC images using the three mentioned scattering models and assembled a respective mosaic for each by correcting the single images for the illumination effects and then normalizing the images to TES albedo data (see Fig. 2). The parameters for the models are estimated using non-linear least square minimization for every single HRSC scene assuming constant parameters over the full image. The results for the Minnaert and the Teillet model appear very consistent by visual inspection. Due to the very high slope angles often appearing in HRSC scenes, the Minnaert model sometimes results in saturated pixels, while the Teillet model achieves the most modest levels of correction. We have not observed any advantage of the Minnaert model over the Teillet model, although it additionally includes emission angle values in the model. This lets us assume that the emission angles have a minor effect on the topography-induced illumination effects. Figure 2: Subsets of the image mosaics; top: uncorrected image mosaic as shown in Michael et al., 2016; middle: Image mosaic with removed shading using the Minnaert scattering model, bottom: Image mosaic with removed shading using the Teillet scattering model.Outlook:The albedo mosaics here serve for a broad range of applications: Image classification using computer vision algorithms, geologic interpretation without influences of the topography and therefore better differentiation between albedo and shading, data fusion with uniform illumination characteristics, as well as the ability to add homogeneous shading from a uniform illumination direction for the application in Virtual Reality scenarios.

This review paper summarizes the observations and results of the Mars Express Mission and its application in the analysis of geological processes and landforms on Mars during the last 20 years. The Mars Express observations provided an extended data base allowing a comparative evaluation of different geological surface landforms and their time-based delimitation. High-resolution imagery and digital elevations models on a local to regional scale and spectral measurements are the basis for geological analyses of water-related surface processes on Mars. This includes the nature and discharges of valley networks, formation timescale of deltas, volumina of sedimentary deposits as well as estimating the age of geological units by crater size–frequency distribution measurements. Both the quantifying of geological processes and the determination of absolute model ages allows to constraint the evolution of Martian water-related activity in space and time. Comparative age estimation of fluvial, glacial, and lacustrine deposits, as well as their timing and episodicity, has revealed the nature and evolution of the Martian surface hydrological cycle. Fluvial and lacustrine activity phases are spread over a time span from Noachian until Amazonian periods, but detailed studies show that they have been interrupted by multiple and long-lasting phases of cessation and quiescent. In addition, evidence of glacial activity shows discrete phases of enhanced intensity correlating with increased spin-axis obliquity amplitude. The episodicity of geological processes, erosion, deposition, and glaciation on Mars demonstrate a close correlation between individual surface processes and endogenic activity as well as spin-axis/orbital variations and changing climate condition.

The South Pole–Aitken (SPA) basin is the oldest and largest visible impact structure on the Moon, making it a high priority science site for exploration missions. The 492 km diameter Apollo peak-ring basin is one of the youngest and largest basins within the SPA basin. We selected three regions of interest (ROIs) in the Apollo basin for which the landing and operational hazards are minimized and evaluated their science and in situ resource utilization (ISRU) potential. We examined topography, slope, crater density, rock abundance, geologic mapping, mineralogy, and inferred subsurface stratigraphy within each ROI. The results show that the terrain is safe for landing without precision landing (within a few hundred meters). The mare materials have high ISRU potential with relatively high FeO (∼16–20 wt%) and TiO _2 (∼3–10 wt%) contents. Two robotic exploration mission architectures were examined for their scientific potential: (1) lander and rover with a dedicated payload suite and (2) the same architecture with sample return capability. In situ observations can address six of seven National Research Council concepts (1–3, 5–7) and Campaigns 1 and 5 of the European Space Agency’s Strategy for Science at the Moon.

. IntroductionThe returned lunar mare soil samples contain highland anorthosites [1]. The source of those non-mare component has been debated since the Apollo epoch ([2]-[9]). In this study, a numerical model was developed to trace the diffusion of non-mare material with the cumulative effect of impact mixing and intermittent filling of mare material.2. ModelIn our previous work [10], a spatially-resolved numerical model was developed to investigate the diffusion of impact melts through impact mixing using the Monte Carlo method. In this study, we extend the capabilities of the model and take into account the volcanic basin infilling forming the lunar mare regions.2.1 Ejecta distributionThe thickness distribution of proximal ejecta with distance from crater center (r) conforms to a power law, typically: δ(r) = Ar-3 [11]. Since the distal ejecta would fade into the background with continuous impact mixing and the thickness distribution becomes more uniform, we assume that the distal ejecta is also continuously distributed, and the thickness is calculated based on the extrapolated power law. Given the value of the minimum deposit thickness (0.01 m), the ejecta coverage range of each impact event can be calculated.2.2 Melt volcanic fillingThe qualitative eruption features of volcanic history of the Moon were pictured showing a trend of eruption flux from high to low but with different peak times [12]. The thickness distribution of volcanic deposits was systematically studied using crater-geometry techniques pioneered by De Hon (Figure 1b, HDeHon). For each mare region, the areas showing the thickest mare deposit are flooded first. As time goes on, mare material accumulates according to the eruption flux. The surrounding areas of thinner mare deposit are subsequently flooded. After the deposit of the youngest volcanic eruption, the thickness of volcanic deposit corresponds to HDeHon. A time step of 0.01 Ga is used to simulate such continuous eruption. At each step, the mare filling occurred within a certain contour region is taken to be uniformly emplaced (Figure 1a). Volcanic eruptions are assumed to initiate soon after the formation of the respective basin. Due to the great volume and the large flooding areas, only the early eruptions are considered [12]. The rough cessation time of the main filling (tend, Figure 1b) among different mare regions is determined based on the areas of differently-aged mare units.3. Results and discussionsGiven the uncertainty in the flux of mare filling, simulations with the varying setting of mare fillings are run to investigate the major factors affecting the non-mare mixing. Figure 2 shows the results when the mare thickness, cessation time of the major mare filling, and the peak time of eruption are taken to be HDeHon, tend and 3.8 Ga, respectively. By taking an average of the results from multiple simulations where the spatial configuration of generated craters is different, the regional differences are averaged out and the general features of non-mare material concentration are obtained. It shows that throughout the mare regions the non-mare component is present. The older mare surfaces accumulate more non-mare material. If most of the mare regions have filled mare material about 500 m in thickness since the formation of basins, the average and median fractions of non-mare components over all the mare regions are both ~0.1. In the top 5m, the average fraction of the non-mare material within 100 km is both about 0.2; between 100 km and 200 km, the non-mare abundance quickly decreases. In the very top surface (1 m) the non-mare abundance is greater. Apollo 11, 17 and Luna 16 located in the relatively old mare regions have the higher abundance of non-mare components (up to ~0.3). The Apollo 15, 12, and Luna 24 sampling sites located in the relatively young mare regions have a less non-mare component (~0.1).By comparing the background composition with the geochemical analysis of the lunar mare soil samples, we infer the most plausible geologic processes that have significantly altered the material composition at the sampling sites: for the Apollo 15 and 17 mare soil samples, the large fraction of non-mare material is likely to have resulted from the downslope slumping or lateral transport of the nearby massifs. The Apollo 12 sampling site has a component of Copernicus ejecta. A mixing of both Copernicus ejecta and excavated local underlying material by high-velocity ejecta has altered the composition at the surface. The non-mare material contained in the Apollo 11 and Luna 24 mare soil samples could have been built up gradually by both long-time lateral and vertical mixing. The mare deposit at the Luna 16 landing site is likely to be relatively thin resulting in the abundant local-origin non-mare component.4. ConclusionsA spatially-resolved numerical model tracing the diffusion of non-mare material was developed to study the source of the non-mare component in the lunar mare soil samples. We find that almost the entirety of the lunar mare regions contains some non-mare components. If the mare thickness is ~500 m, half of the areas possess a fraction ranging from 0.05 to 0.15. By comparing our results with the analysis of the collected soil samples, the most plausible geologic processes that may have altered the non-mare material abundance at the sampling sites are inferred.References[1] Wood J.A. (1970), JGR; [2] Rhodes J.M. (1977), Phil Trans Math Phys Eng Sci, 293-301; [3] Simon S.B. et al. (1982), LPSC, 371-388; [4] Huang Y. et al. (2017), JGR-Planets, 1–23; [5] Head J.W. (1982), The moon and the planets, 26(1), 61–88; [6] Budney C.J. and Lucey P.G. (1988), JGR-Planets, 103(E7), 16855–16870; [7] Evan A.J. (2016), GRL, 43(6), 2445–2455. [8] Aridson R. et al. (1975), The Moon, 13(1–3), 67–79; [9] Hörz, F. (1978), LPSC, 3311–3331; [10] Liu T. et al. (2020), Icarus, 113609. [11] Melosh, H.J. (1989), Oxford University. [12] Head J. W. and Wilson L. (1992), Geochim. Cosmochim. Acta, 56(6), 2155–2175.

Introduction: Large craters and basins that are present on the lunar surface are remants of its early impact history. The relative ages of geological surfaces can be determined with crater size-frequency distribution (CSFD) measurements using a production function (PF), since the impact record on the lunar surface is related to time. Widely used PFs were developed by Neukum (1983) and Neukum et al. (2001) [1,2] and are valid for crater diameters between 0.01–300 km. However, to understand the earlier history of the Moon, when larger impacts were more abundant, an extension of the valid crater diameter range to larger diameters would be beneficial. It could provide input for understanding the number of impactor populations [e.g., 1-4] and the stability of the impact rate on the Moon [e.g., 1,2,5,6]. However, the precise determination of the main basin rim diameter, especially for multi-ring basins, is challenging due to their complex and degraded morphology. Method: The diameters of large craters and basins were measured based on topographic (~100 m/pixel) and gravity data. We used the Lunar Reconnaissance Orbiter (LRO) Wide Angle Camera (WAC) image mosaic [7], LRO Lunar Orbiter Laser Altimeter Digital Elevation Model (LOLA DEM) [8], and the WAC DEM color-shaded relief map [9,10]. In addition, the following geophysical data were used: Gravity Recovery and Interior Laboratory (GRAIL) [11] data, a crustal thickness map (Crustal Thickness – Model 1) [12], and a Bouguer anomaly map [11].In order to have a consistent measurement of the main basin rim diameter, we follow the approach of Neumann et al. (2015) [13]. They [13] compared the Bouguer anomaly, which reflects changes in the subsurface and/or crustal thickness, with well-preserved basin structures. They suggest that double the diameter of the Bouguer anomaly is consistent with the main or reference rim for multi-ring basins.The ArcGIS CraterTools add-in [14] was used to perform the CSFD measurements, which were then further analyzed with Craterstats2 [15]. The count area is the entire Moon, but due to significant differences between mare and highlands areas, we subdivide the count area "Entire Moon" into "Highlands" and "Mare". Results & Discussion: We identified 311 craters and basins with diameters between 100-1250 km over the entire Moon. We do not include the South Pole Aitken (SPA) basin as it is unclear which topographic ring is its reference rim and it is assumed to have formed in an even earlier era of lunar basins [16]. The CSFD measurements (Figure 1) of the entire Moon and the highlands are consistent up to diameters of 250 km. However, while the highlands distribution progresses relatively smoothly towards large basin diameters, the CSFD of the entire Moon shows a "step" between 400-700 km. The CSFD of the mare areas is significantly different from the two other areas. Craters 250 km are more abundant. The CSFD measurements for the entire Moon and the lunar highlands are better represented by the PF of [2] using the valid crater diameter range of 100-300 km. The mare areas could not be fitted with either PF. Figure 1: Cumulative CSFD plots for large craters and basins compared with existing PFs (black and blue curves) (a) [1] and (b) [2] in the valid crater diameter range of 100-300 km. The gray line represents the equilibrium function of [17]. The significant difference between the CSFDs on highlands and mare areas may result from:(1) lava flooding [18,19], causing an incomplete identification of basins on the mare areas(2) asymmetries in cratering rate, e.g. due to the rotation and inclination of the Moon [20,21](3) larger basin diameters resultant on the lunar nearside due to a different subsurface temperature and crustal thickness [16] Conclusion: The CSFD measurements indicate that large craters and basins are still in production and, therefore, an extension of PFs for craters and basins from 300-1250 km could be possible. This extented crater diameter range would allow to draw conclusions about the number of impactor populations and the stability of the impact rate in the early lunar history. However, the influence of resurfacing processes on mare units compared to the highlands is not yet entirely understood and a more detailed analysis of the mare regions is necessary.Acknowledgments: This Project is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – Project-ID 263649064 – TRR 170.References: [1] Neukum G. (1983) Habil. Thesis LMU, Munich. [2] Neukum G. et al. (2001) Space Sci. Rev., 96, 55. [3] Strom R.G. et al. (2005) Science, 309(5742), 1847-1850. [4] Head J.W. et al. (2010) Science, 329(5998), 1504-1507. [5] Guinness E.A. and Arvidson R.E. (1977) Proc. Lunar Sci Conf., 8, 3475-3494. [6] Bottke W.F. et al. (2005) Icarus, 179(1), 63-94. [7] Robinson M.S. et al. (2010) Space Sci. Rev. 150, 81-124. [8] Smith D.E. et al. (2010) Space Sci. Rev., 150, 209-241. [9] Scholten F. et al. (2012) JGR, 117(E12). [10] Smith D.E. et al. (2010) GRL, 37(18). [11] Zuber M.T. et al. (2013) Science, 339(6120), 668-671. [12] Wieczorek M.A. et al. (2013) Science, 339, 671-675. [13] Neumann G.A. et al. (2015) Sci. Adv., 1(9), e1500852. [14] Kneissl T. et al. (2011) PSS, 59(11-12), 1243-1254. [15] Michael G. et al. (2016) Icarus, 277, 279-285. [16] Miljković K. et al. (2013) Science, 342(6159), 724-726. [17] Hartmann W.K. (1984) Icarus, 60(1), 56-74. [18] Evans A.J. (2016) Geophys. Res. Lett., 43, 2445-2455. [19] Evans A.J. (2018) JGR, 123, 1596-1617. [20] Wiesel W. (1973) Icarus, 15(3), 373-383. [21] Le Feuvre M. and Wieczorek M.A. (2011) Icarus, 214(1), 1-20.

Tectonic features on the Moon can reflect the state of stress during the formation of the structure, and sinuous rilles can provide further insight into the tectonic-thermal evolution of the Moon. Manual visual interpretation is the primary method for extracting these linear structures due to their complex morphology. However, extracting these features from the vast amount of lunar remote sensing data requires significant time and effort from researchers, especially for small-scale tectonic features, such as wrinkle ridges, lobate scarps, and high-relief ridges. In order to enhance the efficiency of linear structure detection, this paper conducts research on the automatic detection method of linear structures using sinuous rilles as an example case. In this paper, a multimodal semantic segmentation method, “Sinuous Rille Network (SR-Net)”, for detecting sinuous rilles is proposed based on DeepLabv3+. This method combines advanced techniques such as ECA-ResNet and dynamic feature fusion. Compared to other networks, such as PSPNet, ResUNet, and DeepLabv3+, SR-Net demonstrates superior precision (95.20%) and recall (92.18%) on the multimodal sinuous rille test set. The trained SR-Net was applied in detecting lunar sinuous rilles within the range of 60°S to 60°N latitude. A new catalogue of sinuous rilles was generated based on the results of the detection process. The methodology proposed in this paper is not confined to the detection of sinuous rilles; with further improvements, it can be extended to the detection of other linear structures.

Research Article| December 01, 2023 The Lunar Cratering Chronology H. Hiesinger; H. Hiesinger Institut für Planetologie, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany hiesinger@uni-muenster.de; Search for other works by this author on: GSW Google Scholar C.H. van der Bogert; C.H. van der Bogert Institut für Planetologie, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany vanderbogert@uni-muenster.de Search for other works by this author on: GSW Google Scholar G. Michael; G. Michael Institute of Geological Sciences, Planetary Sciences and Remote Sensing, Freie Universität Berlin, Berlin, Germany Search for other works by this author on: GSW Google Scholar N. Schmedemann; N. Schmedemann Institut für Planetologie, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany Search for other works by this author on: GSW Google Scholar W. Iqbal; W. Iqbal Institut für Planetologie, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany Search for other works by this author on: GSW Google Scholar S.J. Robbins; S.J. Robbins Southwest Research Institute, 1050 Walnut St., Suite 300, Boulder, CO 80302, USA Search for other works by this author on: GSW Google Scholar B. Ivanov; B. Ivanov Institute for Dynamics of Geospheres, Russian Academy of Sciences, Moscow, Russia Search for other works by this author on: GSW Google Scholar J.-P. Williams; J.-P. Williams Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, CA 90095, USA Search for other works by this author on: GSW Google Scholar M. Zanetti; M. Zanetti Marshall Space Flight Center, Huntsville, Alabama, USA Search for other works by this author on: GSW Google Scholar J. Plescia; J. Plescia Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USA Search for other works by this author on: GSW Google Scholar L. R. Ostrach; L. R. Ostrach U.S. Geological Survey, Astrogeology Science Center, 2255 N. Gemini Dr., Flagstaff, Arizona 86001, USA Search for other works by this author on: GSW Google Scholar J.W. Head, III J.W. Head, III Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, Rhode Island, USA Search for other works by this author on: GSW Google Scholar Author and Article Information H. Hiesinger Institut für Planetologie, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany C.H. van der Bogert Institut für Planetologie, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany G. Michael Institute of Geological Sciences, Planetary Sciences and Remote Sensing, Freie Universität Berlin, Berlin, Germany N. Schmedemann Institut für Planetologie, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany W. Iqbal Institut für Planetologie, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany S.J. Robbins Southwest Research Institute, 1050 Walnut St., Suite 300, Boulder, CO 80302, USA B. Ivanov Institute for Dynamics of Geospheres, Russian Academy of Sciences, Moscow, Russia J.-P. Williams Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, CA 90095, USA M. Zanetti Marshall Space Flight Center, Huntsville, Alabama, USA J. Plescia Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USA L. R. Ostrach U.S. Geological Survey, Astrogeology Science Center, 2255 N. Gemini Dr., Flagstaff, Arizona 86001, USA J.W. Head, III Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, Rhode Island, USA hiesinger@uni-muenster.de; vanderbogert@uni-muenster.de Publisher: Mineralogical Society of America First Online: 04 Dec 2023 Copyright © 2023 by the Mineralogical Society of AmericaMineralogical Society of America Reviews in Mineralogy and Geochemistry (2023) 89 (1): 401–451. https://doi.org/10.2138/rmg.2023.89.10 Article history First Online: 04 Dec 2023 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation H. Hiesinger, C.H. van der Bogert, G. Michael, N. Schmedemann, W. Iqbal, S.J. Robbins, B. Ivanov, J.-P. Williams, M. Zanetti, J. Plescia, L. R. Ostrach, J.W. Head; The Lunar Cratering Chronology. Reviews in Mineralogy and Geochemistry 2023;; 89 (1): 401–451. doi: https://doi.org/10.2138/rmg.2023.89.10 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyReviews in Mineralogy and Geochemistry Search Advanced Search The Moon is a unique body in our Solar System that allows us to groundtruth remote-sensing data (e.g., crater size–frequency distributions, or CSFDs, crater/rock degradation rates, mineralogy, composition) of the Apollo and Luna landing sites with well-characterized samples that have been investigated and dated in terrestrial laboratories (e.g., Hartmann 1966; Greeley and Gault 1970; Papanastassiou and Wasserburg 1971; Soderblom 1972; Husain 1974; Nunes et al. 1974; Schaefer and Husain 1974; Tera and Wasserburg 1974; Tera et al. 1974; Neukum et al. 1975a,b; Boyce 1976; Neukum and Horn... 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The timeline of the early lunar bombardment remains unclear. The bombardment rate as a function of time is commonly modeled by three types of shapes: tail-end, sawtooth, and terminal cataclysm. Differently aged melt records the occurrence time of impact events and thus is crucial for constraining the timeline of the early lunar bombardment. Based on a spatially resolved numerical model, we simulate the evolving distribution of differently aged melt with a long-term impact mixing, where different shapes of impact rate function are considered. We compare the outcome of melt age distribution from different scenarios with the actual data from the lunar meteorites and the returned samples. The results suggest that, if the present data are representative of the melt age distribution on the Moon, the shape of the impact rate function is more likely comparable to the tail-end over the sawtooth and the terminal cataclysm, with the terminal cataclysm being least likely. In addition, using state-of-the-art U–Pb dating techniques, more abundant ancient basin melt is likely to be found in returned samples.

Lunar grabens are the largest tensional linear structures on the Moon. In this paper, 17 grabens were selected to investigate the dips and displacement–length ratios (γ) of graben-bounding faults. Several topographic profiles were generated from selected grabens to measure their rim elevation, width and depth through SLDEM2015 (+LOLA) data. The differences in rim elevation (∆h) and width (∆W) between two topographic profiles on each graben were calculated, yielding 146 sets of data. We plotted ∆h vs. ∆W for each and calculated the dip angle (α) of graben-bounding faults. A dip of 39.9° was obtained using the standard linear regression method. In order to improve accuracy, large error data were removed based on error analysis. The results, 49.4° and 52.5°, were derived by the standard linear regression and average methods, respectively. Based on the depth and length of grabens, the γ value of the graben-bounding normal fault is also studied in this paper. The γ value is 3.6 × 10−3 for lunar normal faults according to the study of grabens and the Rupes Recta normal fault. After obtaining the values of α and γ, the increase in lunar radius indicated by the formation of grabens was estimated. We suggest that the lunar radius has increased by approximately 130 m after the formation of grabens. This study could aid in the understanding of normal fault growth and provide important constraints on the thermal evolution of the Moon.

The early impact bombardment extensively fractured the lunar crust resulting in the formation of the so-called megaregolith. Previous estimates of megaregolith distribution vary significantly with respect to the vertical extent and the size-frequency distribution of fragments was rarely studied. We built a spatially resolved numerical model to simulate the process of cumulative impact fragmentation, aiming to backtrack the megaregolith evolution history and to constrain its fragment distribution. The results highlight the pivotal role of basin-forming events on the megaregolith formation. Especially the South -Pole Aitken (SPA) impact established the initial megaregolith structure which remained distinct after 0.5 Ga subsequent fragmentation. At 3.8 Ga, the megaregolith displays substantial lateral variation and layering: the highly fractured upper layer of similar to 2.5 km is dominated by meter-scale fragments; the disturbed lower layer deeper than tens of kilometers is mainly consisting of kilometer-scale fragments; the transition zone >5 km contains fragments of various size scales.(c) 2022 Published by Elsevier B.V.