The national and international progress in deep space exploration has greatly promoted the development of planetary science in China.Substantial progress in different areas of planetary science has been achieved in 20...The national and international progress in deep space exploration has greatly promoted the development of planetary science in China.Substantial progress in different areas of planetary science has been achieved in 2020-2022.In this report,we summarize the research achievements obtained in China in the last three years.The achievements include the research on geology,geochemistry,and space physics of the Moon,Mars,Mercury,Venus,giant planets,asteroids,and comets.The recent work on science objectives,mission payloads,and analytical capabilities that supports the lunar and deep space exploration program of China has also been introduced in this report.Finally,we report the progress on developments of discipline and research team of planetary science in China.展开更多
NWA 6950 is a type of cumulate gabbro meteorite that displays features indicating a lunar origin.Specifically,the Fe/Mn values of olivines and pyroxenes in the meteorite suggest a lunar origin,as does the presence of ...NWA 6950 is a type of cumulate gabbro meteorite that displays features indicating a lunar origin.Specifically,the Fe/Mn values of olivines and pyroxenes in the meteorite suggest a lunar origin,as does the presence of Fe-Ni metal.The meteorite has also undergone intense shock metamorphism,which is evidenced by the presence of ringwoodite,tuite,and xieite(a type of chromite with a CaTi_(2)O_(4)structure)within the shock melt veins(SMVs).The texture,mineral modal abundances,and bulk compositions(measured from the SMVs)of NWA 6950 are similar to those of the NWA 773 clan,as are the concentrations and patterns of rare-earth-elements in olivine,pyroxene,plagioclase,and phosphate.In-situ U-Pb dating of baddeleyite and phosphate in NWA 6950 has determined its crystallization age to be 3133±11 and 3129±23 Ma,which is consistent with age data provided by Shaulis et al.(2017).Further,the chronology of the NWA 773 clan appears to be at least bimodal when considering the age of NWA 3333(3038±20 Ma;Merle et al.,2020).The tight range of ages for the NWA 773 clan at approximately 3.1 Ga coincides with a change in the eruption flux and style on the Moon.This suggests that lunar volcanism may have shifted from extrusivedominated to intrusive-dominated at approximately 3.1 Ga,resulting in the widespread distribution of gabbro lithologies on the Moon.展开更多
The size of basalt fragments in Chang’E-5(CE-5)regolith are small(<6 mm^(2)),resulting in large variation on the estimated bulk composition of CE-5 basalt.For example,the estimated TiO_(2) content of CE-5 basalt r...The size of basalt fragments in Chang’E-5(CE-5)regolith are small(<6 mm^(2)),resulting in large variation on the estimated bulk composition of CE-5 basalt.For example,the estimated TiO_(2) content of CE-5 basalt ranges from 3.7 wt% to 12.7 wt% and the Mg#(molar percentage of Mg/[Mg+Fe])also shows a wide range(26.2-42.4).Preliminary experimental studies have shown that these geochemical characteristics of CE-5 basalt are critical for investigating the crystallization sequence and formation mechanism of its parent magma.This study presents new experimental data on the distribution coefficient of titanium between pyroxene and lunar basaltic magma(D_(Ti)^(Px/melt)).Combining with available literature data,we confirm that D_(Ti)Px/melt is affected by crystallization conditions such as pressure and temperature,but it is mainly controlled by the CaO content of pyroxene.Comparing with previous experimental results under similar conditions,we parameterized the effect as D_(Ti)^(Px/Melt)=D_(Ti)^(Px/Melt)=-0.0005X_(Cao)^(2)+0.0218X_(CaO)+0.0425(R^(2)=0.82),where X_(CaO) is the CaO content in pyroxene in weight percentage.The new experimental results suggest that pyroxene with high TiO_(2) content(>2.5 wt%)in CE-5 basalt is not a product of equilibrium crystallization,and the CaO content in pyroxene is also affected by cooling rate of its parent magma.The TiO_(2) content in the CE-5 parent magma is estimated to be about 5 wt% based on the Mg# of pyroxene and its calculated CaO content,which is consistent with those estimated from olivine grains.展开更多
Permanently shadowed regions(PSRs)on the Moon are potential reservoirs for water ice,making them hot spots for future lunar exploration.The water ice in PSRs would cause distinctive changes in space weathering there,i...Permanently shadowed regions(PSRs)on the Moon are potential reservoirs for water ice,making them hot spots for future lunar exploration.The water ice in PSRs would cause distinctive changes in space weathering there,in particular reduction-oxidation processes that diff er from those in illuminated regions.To determine the characteristics of products formed during space weathering in PSRs,the lunar meteorite NWA 10203 with artifi cially added water was irradiated with a nanosecond laser to simulate a micro-meteorite bombardment of lunar soil containing water ice.The TEM results of the water-incorporated sample showed distinct amorphous rims that exhibited irregular thickness,poor stratifi cation,the appearance of bubbles,and a reduced number of npFe^(0).Additionally,EELS analysis showed the presence of ferric iron at the rim of the nanophase metallic iron particles(npFe^(0))in the amorphous rim with the involvement of water.The results suggest that water ice is another possible factor contributing to oxidation during micrometeorite bombardment on the lunar surface.In addition,it off ers a reference for a new space weathering model that incorporates water in PSRs,which could be widespread on asteroids with volatiles.展开更多
Forty-five years after the Apollo and Luna missions, China’s Chang’e-5 (CE-5) mission collected ∼1.73 kg of new lunar materials from one ofthe youngest basalt units on the Moon. The CE-5 lunar samples provide oppor...Forty-five years after the Apollo and Luna missions, China’s Chang’e-5 (CE-5) mission collected ∼1.73 kg of new lunar materials from one ofthe youngest basalt units on the Moon. The CE-5 lunar samples provide opportunities to address some key scientific questions related to theMoon, including the discovery of high-pressure silica polymorphs (seifertite and stishovite) and a new lunar mineral, changesite-(Y). Seifertitewas found to be coexist with stishovite in a silica fragment from CE-5 lunar regolith. This is the first confirmed seifertite in returned lunarsamples. Seifertite has two space group symmetries (Pnc2 and Pbcn) and formed from an α-cristobalite-like phase during “cold” compressionduring a shock event. The aftershock heating process changes some seifertite to stishovite. Thus, this silica fragment records different stagesof an impact process, and the peak shock pressure is estimated to be ∼11 to 40 GPa, which is much lower than the pressure condition forcoexistence of seifertite and stishovite on the phase diagram. Changesite-(Y), with ideal formula (Ca_(8)Y)◻Fe^(2+)(PO_(4))_(7) (where ◻ denotes avacancy) is the first new lunar mineral to be discovered in CE-5 regolith samples. This newly identified phosphate mineral is in the form ofcolumnar crystals and was found in CE-5 basalt fragments. It contains high concentrations of Y and rare earth elements (REE), reaching upto ∼14 wt. % (Y,REE)2O3. The occurrence of changesite-(Y) marks the late-stage fractional crystallization processes of CE-5 basalts combinedwith silicate liquid immiscibility. These new findings demonstrate the significance of studies on high-pressure minerals in lunar materials andthe special nature of lunar magmatic evolution.展开更多
INTRODUCTION Japan’s first successful lunar landing mission,Smart Lander for Investigating Moon(SLIM),was landed on the Moon on January 19th,2024.SLIM made a precise landing within 100 m of the targeted landing zone(...INTRODUCTION Japan’s first successful lunar landing mission,Smart Lander for Investigating Moon(SLIM),was landed on the Moon on January 19th,2024.SLIM made a precise landing within 100 m of the targeted landing zone(central coordinates 13.316°S,25.251°E),which is located around the Shioli crater(D=270 m,central coordinates as 13.33°S,25.23°E)in the southwestern ejecta of the Theophilus crater(D=98.6 km,central coordinates as 11.45°S,26.28°E).展开更多
Space metallurgy is an interdisciplinary field that combines planetary space science and metallurgical engineering.It involves systematic and theoretical engineering technology for utilizing planetary resources in sit...Space metallurgy is an interdisciplinary field that combines planetary space science and metallurgical engineering.It involves systematic and theoretical engineering technology for utilizing planetary resources in situ.However,space metallurgy on the Moon is challenging because the lunar surface has experienced space weathering due to the lack of atmosphere and magnetic field,making the mi-crostructure of lunar soil differ from that of minerals on the Earth.In this study,scanning electron microscopy and transmission electron microscopy analyses were performed on Chang’e-5 powder lunar soil samples.The microstructural characteristics of the lunar soil may drastically change its metallurgical performance.The main special structure of lunar soil minerals include the nanophase iron formed by the impact of micrometeorites,the amorphous layer caused by solar wind injection,and radiation tracks modified by high-energy particle rays inside mineral crystals.The nanophase iron presents a wide distribution,which may have a great impact on the electromagnetic prop-erties of lunar soil.Hydrogen ions injected by solar wind may promote the hydrogen reduction process.The widely distributed amorph-ous layer and impact glass can promote the melting and diffusion process of lunar soil.Therefore,although high-energy events on the lun-ar surface transform the lunar soil,they also increase the chemical activity of the lunar soil.This is a property that earth samples and tradi-tional simulated lunar soil lack.The application of space metallurgy requires comprehensive consideration of the unique physical and chemical properties of lunar soil.展开更多
The Moon has been divided into three terranes:Procellarum KREEP Terrane(PKT),Feldspathic Highland Terrane(FHT),and South Pole-Aitken Terrane(SPAT),using globally measured Th and FeO.Many lunar evolu-tion models have p...The Moon has been divided into three terranes:Procellarum KREEP Terrane(PKT),Feldspathic Highland Terrane(FHT),and South Pole-Aitken Terrane(SPAT),using globally measured Th and FeO.Many lunar evolu-tion models have predicted that a lunar magma ocean will produce a residual layer enriched in incompatible elements such as K,REE,and P(i.e.,KREEP)in the late age of crys-tallization;and that the distribution of thorium can be used as a proxy for determining the global distribution of KREEP.The thorium distribution in these three terranes is inhomo-geneous.The highest concentration of thorium is in PKT,the medium concentration of thorium is in SPAT,and almost none in FHT.Then what is the specific distribution in each of the terrane and what enlightenment can it tell us?Here we present and describe the detailed thorium distribution in PKT,SPAT,and FHT and provide some information for the origin of asymmetries on the lunar surface.展开更多
Perchlorate and chlorate are present in various extraterrestrial celestial bodies throughout the solar system,such as Mars,the moon,and asteroids.To date,the origin mechanisms of perchlorate and chlorate on the Martia...Perchlorate and chlorate are present in various extraterrestrial celestial bodies throughout the solar system,such as Mars,the moon,and asteroids.To date,the origin mechanisms of perchlorate and chlorate on the Martian surface have been well-established;however,relatively little attention has been cast to airless bodies.Here,we experimentally investigated the potential oxidation mechanisms of chloride to chlorate and perchlorate,such as ultraviolet irradiation under H_(2)O-and O_(2)-free conditions and mechanical pulverization processes.Individual minerals,olivine,pyroxene,ilmenite,magnetite,TiO_(2)and anhydrous ferric sulfate,and lunar regolith simulants(low Ti,CLRS-1;high-Ti,CLRS-2)and their metallic iron(Fe^( 0))bearing counterparts were examined.We found that pulverization of dry matrix material-halite mixtures,even in the presence of O_(2),does not necessarily lead to perchlorate and chlorate formation without involving water.Under photocatalytic and H_(2)O and O_(2)-free conditions,olivine and pyroxene can produce oxychlorine(ClO_(x)^(−))species,although the yields were orders of magnitude lower than those under Martian-relevant conditions.Nanophase-Fe^(0)particles in the lunar regolith and the common photocatalyst TiO_(2)can facilitate the ClO_(x)^(−)formation,but their yields were lower than those with olivine.The oxides ilmenite and magnetite did not efficiently contribute to ClO_(x)^(−)production.Our results highlight the critical role of H_(2)O in the oxidation chloride to chlorate and perchlorate,and provide essential insights into the environmental influence on the formation of oxychlorine species on different celestial bodies.展开更多
Space weathering is a primary factor in altering the composition and spectral characteristics of surface materials on airless planets.However,current research on space weathering focuses mainly on the Moon and certain...Space weathering is a primary factor in altering the composition and spectral characteristics of surface materials on airless planets.However,current research on space weathering focuses mainly on the Moon and certain types of asteroids.In particular,the impacts of meteoroids and micrometeoroids,radiation from solar wind/solar flares/cosmic rays,and thermal fatigue due to temperature variations are being studied.Space weathering produces various transformation products such as melted glass,amorphous layers,iron particles,vesicles,and solar wind water.These in turn lead to soil maturation,changes in visible and near-infrared reflectance spectra(weakening of characteristic absorption peaks,decreased reflectance,increased near-infrared slope),and alterations in magnetism(related to small iron particles),collectively termed the“lunar model”of space weathering transformation.Compared to the Moon and asteroids,Mercury has unique spatial environmental characteristics,including more intense meteoroid impacts and solar thermal radiation,as well as a weaker particle radiation environment due to the global distribution of its magnetic field.Therefore,the lunar model of space weathering may not apply to Mercury.Previous studies have extensively explored the eff ects of micrometeoroid impacts.Hence,this work focuses on the eff ects of solar-wind particle radiation in global magnetic-field distribution and on the weathering transformation of surface materials on Mercury under prolonged intense solar irradiation.Through the utilization of highvalence state,heavy ion implantation,and vacuum heating simulation experiments,this paper primarily investigates the weathering transformation characteristics of the major mineral components such as anorthite,pyroxene,and olivine on Mercury’s surface and compares them to the weathering transformation model of the Moon.The experimental results indicate that ion implantation at room temperature is insufficient to generate np-Fe^(0)directly but can facilitate its formation,while prolonged exposure to solar thermal radiation on Mercury’s surface can lead directly to the formation of np-Fe^(0).Therefore,intense solar thermal radiation is a crucial component of the unique space weathering transformation process on Mercury’s surface.展开更多
The Ideale section(IS)at Montalbano Jonico,Italy,has been approved as a Standard Auxiliary Boundary Stratotype(SABS)for the Global boundary Stratotype Section and Point(GSSP)of the Middle Pleistocene Subseries/Subepoc...The Ideale section(IS)at Montalbano Jonico,Italy,has been approved as a Standard Auxiliary Boundary Stratotype(SABS)for the Global boundary Stratotype Section and Point(GSSP)of the Middle Pleistocene Subseries/Subepoch and Chibanian Stage/Age at the Chiba section,Japan.The proposal was submitted to the voting members of the International Commission on Stratigraphy’s Subcommission on Quaternary Stratigraphy(SQS)on May 4,2023,and following discussions was approved on July 8,2023.The 74 m thick IS continuously spans the Marine Isotope Stage(MIS)20–18 interval,and is part of the longer Montalbano Jonico succession(Basilicata,southern Italy in the Mediterranean region)encompassing MIS 37 to early MIS 16.The IS provides a detailed record based on multiple chronologically well constrained marine and terrestrial proxies,which are particularly useful for outlining the paleoclimatic evolution through the Lower–Middle Pleistocene transition.The high-resolution carbon and oxygen isotope stratigraphy outlines glacial–interglacial and stadial–interstadial phases as well as the sub-millennialscale features of Termination IX and the onset of MIS 19c.The sapropel layer equivalent to insolation cycle 74(784 ka)occurs in early MIS 19c.A prominent peak in the 10Be/9Be record at the MIS 19c–19b transition identifies the low geomagnetic dipole moment associated with the Matuyama–Brunhes boundary interval.Two tephra layers(V3 and V4)relevant to boundary interval are 40Ar/39Ar dated.The V4 layer,occurring at the MIS 19c–b transition and in the middle of the 10Be/9Be peak,has an age of 774.1±0.9 ka,corresponding to the age of the Middle Pleistocene GSSP.A high-resolution alkenone sea-surface temperature and several paleobiological records complement the rich chronological and paleoenvironmental dataset from MIS 20 to the inception of MIS 18.The GSSP boundary interval in the IS is represented from 35.50 to 39.50 m,which corresponds to the interval of the highest values of the 10Be/9Be ratio(~776.35–771.87 ka)and includes the V4 tephra layer and the MIS 19c–MIS 19b transition.This SABS extends the correlation potential of the Middle Pleistocene Subseries/Subepoch GSSP interval to the Mediterranean region.展开更多
The Chang＇e-3（CE-3） spacecraft successfully landed on one of the youngest mare surfaces on the Moon in December 2013. The Yutu rover carried by CE-3 was equipped with a radar system that could reveal subsurface str...The Chang＇e-3（CE-3） spacecraft successfully landed on one of the youngest mare surfaces on the Moon in December 2013. The Yutu rover carried by CE-3 was equipped with a radar system that could reveal subsurface structures in unprecedented details, which would facilitate understanding regional and global evolutionary history of the Moon. Based on regional geology, cratering scaling, and morphological study, here we quantify the subsurface structures of the landing site using high-resolution orbital and in-situ imagery data. Three layers of lunar regolith, two layers of basalt units, and one layer of ejecta deposits are recognized at the subsurface of the landing site, and their thicknesses are deduced based on the imagery data. These results could serve as essential references for the on-going interpretation of the CE-3 radar data. The ability to validate our theoretical subsurface structure using CE-3 in-situ radar observations will improve the methods for quantifying lunar subsurface structure using crater morphologies and scaling.展开更多
The 2008 Nura Mw6.7 earthquake occurred in front of the Trans-Alai Range, central Asia. We present Interferometric Synthetic Aperture Radar （InSAR） measurements of its coseismic ground deformation that are available...The 2008 Nura Mw6.7 earthquake occurred in front of the Trans-Alai Range, central Asia. We present Interferometric Synthetic Aperture Radar （InSAR） measurements of its coseismic ground deformation that are available for a major earthquake in the region. Analysis of the InSAR data shows that the earthquake ruptured a secondary fault of the Main Pamir Thrust for about 20 kin. The fault plane striking N46~E and dipping 48~SE is dominated by thrust slip up to 3 m, most of which is confined to the uppermost 2-5 km of the crust, similar to the nearby 1974 MwT.0 Markansu earthquake. The elastic model of interseismic deformation constrained by GPS measurements suggests that the two earthquakes may have resulted from the failures of two high-angle reverse faults that are about 10 km apart and rooted in a locked dScollement at depths of 5-6 kin. The elastic strain is built up by a freely creeping decollement at about 16 mm/a.展开更多
Over 600 chloride-bearing deposits(chlorides) have been identified on the southern highlands of Mars. These chlorides have critical implications for hydrology and astrobiology: they are indicators of an evaporating su...Over 600 chloride-bearing deposits(chlorides) have been identified on the southern highlands of Mars. These chlorides have critical implications for hydrology and astrobiology: they are indicators of an evaporating super saturated solution, and they could have provided habitat environments for halophilic microorganisms and preserved organic matter. One of the prominent geomorphology characteristics of these chloridebearing regions is the polygonal features within them. The origin of these polygonal features is still in debate. In this study, we have surveyed 153 locations of chlorides using 441 high resolution imaging science experiment(Hi RISE) images to characterize the geomorphology of polygonal features. We identified 3 types of polygonal features of distinct geomorphologic characteristics: fractures, raised ridges, and transitional polygons between fractures and raised ridges. We evaluate previously proposed hypotheses of the formation of the polygonal features, and suggest that the 3 types of polygonal features are indicators of different stages of salt crust formation. Salt crust is usually formed through multiple groundwater activities, and it often occurs in playa environment on Earth. The unique hydrological and astrobiological implications of the chlorides with polygonal features make these deposits of high priority for future landed on and/or sample return exploration missions of Mars.展开更多
We review previously published and newly obtained crater size-frequency distributions in the inner solar system. These data indicate that the Moon and the ter- restrial planets have been bombarded by two populations o...We review previously published and newly obtained crater size-frequency distributions in the inner solar system. These data indicate that the Moon and the ter- restrial planets have been bombarded by two populations of objects. Population 1, dominating at early times, had nearly the same size distribution as the present-day asteroid belt, and produced heavily cratered surfaces with a complex, multi-sloped crater size-frequency distribution. Population 2, dominating since about 3.8-3.7 Gyr, had the same size distribution as near-Earth objects （NEOs） and a much lower im- pact flux, and produced a crater size distribution characterized by a differential -3 single-slope power law in the crater diameter range 0.02 km to 100 km. Taken to- gether with the results from a large body of work on age-dating of lunar and meteorite samples and theoretical work in solar system dynamics, a plausible interpretation of these data is as follows. The NEO population is the source of Population 2 and it has been in near-steady state over the past ～ 3.7-3.8 Gyr; these objects are derived from the main asteroid belt by size-dependent non-gravitational effects that favor the ejection of smaller asteroids. However, Population 1 was composed of main belt as- teroids ejected from their source region in a size-independent manner, possibly by means of gravitational resonance sweeping during orbit migration of giant planets; this caused the so-called Late Heavy Bombardment （LHB）. The LHB began some time before ～3.9 Gyr, peaked and declined rapidly over the next ～ 100 to 300 Myr, and possibly more slowly from about 3.8-3.7 Gyr to ～2 Gyr. A third crater population （Population S） consisted of secondary impact craters that can dominate the cratering record at small diameters.展开更多
Marius Hills is a volcanic plateau on the nearside of the Moon. It is of great interest for its high concentration of volcanic features, including domes, cones, ridges, and rilles. However, the morphological and chron...Marius Hills is a volcanic plateau on the nearside of the Moon. It is of great interest for its high concentration of volcanic features, including domes, cones, ridges, and rilles. However, the morphological and chronological characteristics of this plateau were not well studied due to the low resolution of early mission data. This study describes the detailed morphology of the volcanic features using the latest high spatial resolution images of the Terrain Camera （TC） onboard Selene-1 （10 m/pix） and Narrow Angle Camera （NAC） onboard the Lunar Reconnaissance Orbiter （LRO） （0.5 m/pix）. We report here some new structures such as skylights and remnants of lava tubes. We have divided spectrally homogenous areas with Clementine UVVIS data and did crater size frequency distribution （CSFD） measurements with Lunar Orbiter （LO） IV and TC images in every spectral unit. We first report absolute model ages of 1.10 Ga for Marius basalt 1, 1.49 Ga for Fiamsteed basalt, and 1.46 Ga for Schiaparelli Basalt. In addition, we have identified several younger lava events： they are Marius basalt 2 （814 Ma）, medium to low titanium basalt （949 Ma）, and undifferentiated medium titanium basalt （687 Ma）. Finally, we propose a mantle plume scenario for the formation of Marius Hills, which could solve the inconsistency of previous models.展开更多
With the increasing precision of the GRAIL gravity field models and topography from LOLA, it is possible to investigate the substructure beneath crater Clavius. An admittance between gravity and topography data is com...With the increasing precision of the GRAIL gravity field models and topography from LOLA, it is possible to investigate the substructure beneath crater Clavius. An admittance between gravity and topography data is commonly used to estimate selenophysical parameters, including load ratio, crustal thickness and density, and elastic thickness. Not only a surface load, but also a subsurface load is considered in estimation. The algorithm of particle swarm optimization(PSO) with a swarm size of 400 is employed as well.Results indicate that the observed admittance is best-fitted by the modeled admittance based on a spherical shell model, which was proved to be unsatisfactory in the previous study. The best-fitted load ratio f is around-0.194. Such a small load ratio conforms to the direct proportion between the nearly uncompensated topography and its corresponding negative gravity anomaly. It also indicates that a surface load dominates all the loads. Constrained within 2σSTD, a small crustal thickness(～30 km) and a crustal density of ～2587 kg m-3are found, quite close to the results from previous GRAIL research. Considering the well constrained crustal thickness and density, the best-fitted elastic thickness(～7 km) is rational. This result is slightly smaller than the previous study(～12 km). Such difference can be attributed to the difference in crustal density used and the precision of gravity and topography data. Considering that the small difference between the modeled gravity anomaly and observations is quite small, a parameter inversed here could be an indicator of the subsurface structure beneath Clavius.展开更多
Yardangs are wind-eroded ridges usually observed in arid regions on Earth and other planets. Previous geomorphology studies of terrestrial yardang fields depended on satellite data and limited fieldwork. The geometry ...Yardangs are wind-eroded ridges usually observed in arid regions on Earth and other planets. Previous geomorphology studies of terrestrial yardang fields depended on satellite data and limited fieldwork. The geometry measurements of those yardangs based on satellite data are limited to the length, the width, and the spacing between the yardangs; elevations could not be studied due to the relatively low resolution of the satellite acquired elevation data, e.g. digital elevation models(DEMs). However, the elevation information(e.g. heights of the yardang surfaces) and related information(e.g. slope) of the yardangs are critical to understanding the characteristics and evolution of these aeolian features. Here we report a novel approach, using unmanned aerial vehicles(UAVs) to generate centimeterresolution orthomosaics and DEMs for the study of whaleback yardangs in Qaidam Basin, NW China. The ultra-high-resolution data provide new insights into the geomorphology characteristics and evolution of the whaleback yardangs in Qaidam Basin. These centimeter-resolution datasets also have important potential in:(1) high accuracy estimation of erosion volume;(2) modeling in very fine scale of wind dynamics related to yardang formation;(3) detailed comparative planetary geomorphology study for Mars, Venus, and Titan.展开更多
With the increasing scarcity of Earth’s resources and the development of space science and technology,the exploration, development, and utilization of deep space-specific material resources(minerals, water ice, volat...With the increasing scarcity of Earth’s resources and the development of space science and technology,the exploration, development, and utilization of deep space-specific material resources(minerals, water ice, volatile compounds, etc.) are not only important to supplement the resources and reserves on Earth but also provide a material foundation for establishing extraterrestrial research bases. To achieve large depth in-situ condition-preserved coring(ICP-Coring) in the extreme lunar environment, first, lunar rock simulant was selected(SZU-1), which has a material composition, element distribution, and physical and mechanical properties that are approximately equivalent to those of lunar mare basalt. Second, the influence of the lunar-based in-situ environment on the phase, microstructure, and thermal physical properties(specific heat capacity, thermal conductivity, thermal diffusivity, and thermal expansion coefficient)of SZU-1 was explored and compared with the measured lunar rock data. It was found that in an air atmosphere, low temperature has a more pronounced effect on the relative content of olivine than other temperatures, while in a vacuum atmosphere, the relative contents of olivine and anorthite are significantly affected only at temperatures of approximately-20 and 200 ℃. When the vacuum level is less than100 Pa, the contribution of air conduction can be almost neglected, whereas it becomes dominant above this threshold. Additionally, as the testing temperature increases, the surface of SZU-1 exhibits increased microcracking, fracture opening, and unevenness, while the specific heat capacity, thermal conductivity,and thermal expansion coefficient show nonlinear increases. Conversely, the thermal diffusivity exhibits a nonlinear decreasing trend. The relationship between thermal conductivity, thermal diffusivity, and temperature can be effectively described by an exponential function(R^(2)>0.98). The research results are consistent with previous studies on real lunar rocks. These research findings are expected to be applied in the development of the test and analysis systems of ICP-Coring in a lunar environment and the exploration of the mechanism of machine-rock interaction in the in-situ drilling and coring process.展开更多
The Moscoviense basin is an atypical lunar impact basin with concentric rings of positive and negative gravity anomalies. This basin can provide insights into the inhomogeneous thermal activities across the farside of...The Moscoviense basin is an atypical lunar impact basin with concentric rings of positive and negative gravity anomalies. This basin can provide insights into the inhomogeneous thermal activities across the farside of the Moon. Based on an updated spherical harmonic thin elastic-shell loading model, we used localized admittance analyses to estimate the elastic thickness as well as other associated selenophysical parameters for the Moscoviense basin. The high precision gravity and topography data employed in our estimation were collected by the Gravity Recovery and Interior Laboratory and the Lunar Orbiter Laser Altimeter missions. Our results indicate that the crust-mantle interface is mainly compensated by the prefilling depth rather than the observed surface topography. The results constrained within two standard deviations yielded a small load ratio(~0.168), a best-fit crustal thickness of 36.2 km, and an optimized crustal density of 3159.5 kg m-3. Such large density approaches the density of olivine-rich mantle materials, implying that the excavation of the Mare Moscoviense occurred during a basin-forming impact. The inversed elastic thickness at Mare Moscoviense was around 18 km, lower than the previous results(~60 km) found over Mare basins on the lunar nearside. These results indicate that extreme thermal activity existed during the Moscoviense basin-forming period such as reheating mechanisms from a double-impact process and mare volcanism.展开更多
基金Supported by National Natural Science Foundation of China(41941002,41922031,42125303)China National Space Administration(D020205)。
文摘The national and international progress in deep space exploration has greatly promoted the development of planetary science in China.Substantial progress in different areas of planetary science has been achieved in 2020-2022.In this report,we summarize the research achievements obtained in China in the last three years.The achievements include the research on geology,geochemistry,and space physics of the Moon,Mars,Mercury,Venus,giant planets,asteroids,and comets.The recent work on science objectives,mission payloads,and analytical capabilities that supports the lunar and deep space exploration program of China has also been introduced in this report.Finally,we report the progress on developments of discipline and research team of planetary science in China.
基金supported by a pre-research project on Civil Aerospace Technologies funded by CNSA(No.D020205)the Natural Science Foundation of China(Nos.42241156)+1 种基金the CUG outstanding youth team project(No.G1323523042)the Central Public-interest Scientific Institution Basal Research Fund for Institute of Geology,CAGS(No.J1904)。
文摘NWA 6950 is a type of cumulate gabbro meteorite that displays features indicating a lunar origin.Specifically,the Fe/Mn values of olivines and pyroxenes in the meteorite suggest a lunar origin,as does the presence of Fe-Ni metal.The meteorite has also undergone intense shock metamorphism,which is evidenced by the presence of ringwoodite,tuite,and xieite(a type of chromite with a CaTi_(2)O_(4)structure)within the shock melt veins(SMVs).The texture,mineral modal abundances,and bulk compositions(measured from the SMVs)of NWA 6950 are similar to those of the NWA 773 clan,as are the concentrations and patterns of rare-earth-elements in olivine,pyroxene,plagioclase,and phosphate.In-situ U-Pb dating of baddeleyite and phosphate in NWA 6950 has determined its crystallization age to be 3133±11 and 3129±23 Ma,which is consistent with age data provided by Shaulis et al.(2017).Further,the chronology of the NWA 773 clan appears to be at least bimodal when considering the age of NWA 3333(3038±20 Ma;Merle et al.,2020).The tight range of ages for the NWA 773 clan at approximately 3.1 Ga coincides with a change in the eruption flux and style on the Moon.This suggests that lunar volcanism may have shifted from extrusivedominated to intrusive-dominated at approximately 3.1 Ga,resulting in the widespread distribution of gabbro lithologies on the Moon.
基金funded by National natural Science Foundation of China(41973058 and 42473052)the B-type Strategic Priority Research Program of Chinese Academy of Sciences(XDB41020305)National Key and Development Program of China(2024YFF0807500).
文摘The size of basalt fragments in Chang’E-5(CE-5)regolith are small(<6 mm^(2)),resulting in large variation on the estimated bulk composition of CE-5 basalt.For example,the estimated TiO_(2) content of CE-5 basalt ranges from 3.7 wt% to 12.7 wt% and the Mg#(molar percentage of Mg/[Mg+Fe])also shows a wide range(26.2-42.4).Preliminary experimental studies have shown that these geochemical characteristics of CE-5 basalt are critical for investigating the crystallization sequence and formation mechanism of its parent magma.This study presents new experimental data on the distribution coefficient of titanium between pyroxene and lunar basaltic magma(D_(Ti)^(Px/melt)).Combining with available literature data,we confirm that D_(Ti)Px/melt is affected by crystallization conditions such as pressure and temperature,but it is mainly controlled by the CaO content of pyroxene.Comparing with previous experimental results under similar conditions,we parameterized the effect as D_(Ti)^(Px/Melt)=D_(Ti)^(Px/Melt)=-0.0005X_(Cao)^(2)+0.0218X_(CaO)+0.0425(R^(2)=0.82),where X_(CaO) is the CaO content in pyroxene in weight percentage.The new experimental results suggest that pyroxene with high TiO_(2) content(>2.5 wt%)in CE-5 basalt is not a product of equilibrium crystallization,and the CaO content in pyroxene is also affected by cooling rate of its parent magma.The TiO_(2) content in the CE-5 parent magma is estimated to be about 5 wt% based on the Mg# of pyroxene and its calculated CaO content,which is consistent with those estimated from olivine grains.
基金support from the Youth Innovation Promotion Association,Chinese Academy of Sciences(2020395)Strategic Priority Research Program of the Chinese Academy of Sciences grant XDB 41000000(Y.L.)+4 种基金National Natural Science Foundation of China(Nos.42273042 and 41931077)"From 0 to 1"Original Exploration Cultivation Project,Institute of Geochemistry,Chinese Academy of Sciences(DHSZZ2023-3)Guizhou Provincial Foundation for Excellent Scholars Program(No.GCC[2023]088)Guizhou Provincial Science and Technology Projects:QKHJCZK[2023]-General 473NSFC Young Scientist Fund(Nos.42303041 and 42403043)。
文摘Permanently shadowed regions(PSRs)on the Moon are potential reservoirs for water ice,making them hot spots for future lunar exploration.The water ice in PSRs would cause distinctive changes in space weathering there,in particular reduction-oxidation processes that diff er from those in illuminated regions.To determine the characteristics of products formed during space weathering in PSRs,the lunar meteorite NWA 10203 with artifi cially added water was irradiated with a nanosecond laser to simulate a micro-meteorite bombardment of lunar soil containing water ice.The TEM results of the water-incorporated sample showed distinct amorphous rims that exhibited irregular thickness,poor stratifi cation,the appearance of bubbles,and a reduced number of npFe^(0).Additionally,EELS analysis showed the presence of ferric iron at the rim of the nanophase metallic iron particles(npFe^(0))in the amorphous rim with the involvement of water.The results suggest that water ice is another possible factor contributing to oxidation during micrometeorite bombardment on the lunar surface.In addition,it off ers a reference for a new space weathering model that incorporates water in PSRs,which could be widespread on asteroids with volatiles.
基金supported by the B-Type Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB 41000000)the National Natural Science Foundation of China(Grant Nos.41773052,41973058,and 42003054)+2 种基金the Key Research Program of the Chinese Academy of Sciences(Grant No.ZDBS-SSWJSC007-10)the Pre-Research Project on Civil Aerospace Technologies funded by the CNSA(Grant No.D020201)the China Postdoctoral Science Foundation(Grant No.2020M680155).
文摘Forty-five years after the Apollo and Luna missions, China’s Chang’e-5 (CE-5) mission collected ∼1.73 kg of new lunar materials from one ofthe youngest basalt units on the Moon. The CE-5 lunar samples provide opportunities to address some key scientific questions related to theMoon, including the discovery of high-pressure silica polymorphs (seifertite and stishovite) and a new lunar mineral, changesite-(Y). Seifertitewas found to be coexist with stishovite in a silica fragment from CE-5 lunar regolith. This is the first confirmed seifertite in returned lunarsamples. Seifertite has two space group symmetries (Pnc2 and Pbcn) and formed from an α-cristobalite-like phase during “cold” compressionduring a shock event. The aftershock heating process changes some seifertite to stishovite. Thus, this silica fragment records different stagesof an impact process, and the peak shock pressure is estimated to be ∼11 to 40 GPa, which is much lower than the pressure condition forcoexistence of seifertite and stishovite on the phase diagram. Changesite-(Y), with ideal formula (Ca_(8)Y)◻Fe^(2+)(PO_(4))_(7) (where ◻ denotes avacancy) is the first new lunar mineral to be discovered in CE-5 regolith samples. This newly identified phosphate mineral is in the form ofcolumnar crystals and was found in CE-5 basalt fragments. It contains high concentrations of Y and rare earth elements (REE), reaching upto ∼14 wt. % (Y,REE)2O3. The occurrence of changesite-(Y) marks the late-stage fractional crystallization processes of CE-5 basalts combinedwith silicate liquid immiscibility. These new findings demonstrate the significance of studies on high-pressure minerals in lunar materials andthe special nature of lunar magmatic evolution.
基金supported by the National Natural Science Foundation of China(Nos.42241108,42302263,62227901)the Strategic Priority Research Program of Chinese Academy of Science(No.XDB41000000).
文摘INTRODUCTION Japan’s first successful lunar landing mission,Smart Lander for Investigating Moon(SLIM),was landed on the Moon on January 19th,2024.SLIM made a precise landing within 100 m of the targeted landing zone(central coordinates 13.316°S,25.251°E),which is located around the Shioli crater(D=270 m,central coordinates as 13.33°S,25.23°E)in the southwestern ejecta of the Theophilus crater(D=98.6 km,central coordinates as 11.45°S,26.28°E).
基金CNSA for providing access to the lunar sample CE5C0200YJFM00302funding support from the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB 41000000)+5 种基金the National Natural Science Foundation of China (Nos. 42273042 and 41931077)the Youth Innovation Promotion Association Chinese Academy of Sciences (No. 2020395)Key Research Program of Frontier Sciences, Chinese Academy of Sciences (Nos. ZDBS-SSW-JSC00710 and QYZDY-SSW-DQC028)the Young and Middleaged Academic Technology Leader Reserve Talent Project of Yunnan Province (No. 2018HB009)the Science Fund for Outstanding Youth of Yunnan Province (No. 202101 AV070007)the "From 0 to 1" Original Exploration Cultivation Project, Institute of Geochemistry, Chinese Academy of Sciences (No. DHSZZ2023-3)
文摘Space metallurgy is an interdisciplinary field that combines planetary space science and metallurgical engineering.It involves systematic and theoretical engineering technology for utilizing planetary resources in situ.However,space metallurgy on the Moon is challenging because the lunar surface has experienced space weathering due to the lack of atmosphere and magnetic field,making the mi-crostructure of lunar soil differ from that of minerals on the Earth.In this study,scanning electron microscopy and transmission electron microscopy analyses were performed on Chang’e-5 powder lunar soil samples.The microstructural characteristics of the lunar soil may drastically change its metallurgical performance.The main special structure of lunar soil minerals include the nanophase iron formed by the impact of micrometeorites,the amorphous layer caused by solar wind injection,and radiation tracks modified by high-energy particle rays inside mineral crystals.The nanophase iron presents a wide distribution,which may have a great impact on the electromagnetic prop-erties of lunar soil.Hydrogen ions injected by solar wind may promote the hydrogen reduction process.The widely distributed amorph-ous layer and impact glass can promote the melting and diffusion process of lunar soil.Therefore,although high-energy events on the lun-ar surface transform the lunar soil,they also increase the chemical activity of the lunar soil.This is a property that earth samples and tradi-tional simulated lunar soil lack.The application of space metallurgy requires comprehensive consideration of the unique physical and chemical properties of lunar soil.
基金This work was supported by National Key Research and Development Program of China(Grant No.2022YFF0503100)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB 41000000).
文摘The Moon has been divided into three terranes:Procellarum KREEP Terrane(PKT),Feldspathic Highland Terrane(FHT),and South Pole-Aitken Terrane(SPAT),using globally measured Th and FeO.Many lunar evolu-tion models have predicted that a lunar magma ocean will produce a residual layer enriched in incompatible elements such as K,REE,and P(i.e.,KREEP)in the late age of crys-tallization;and that the distribution of thorium can be used as a proxy for determining the global distribution of KREEP.The thorium distribution in these three terranes is inhomo-geneous.The highest concentration of thorium is in PKT,the medium concentration of thorium is in SPAT,and almost none in FHT.Then what is the specific distribution in each of the terrane and what enlightenment can it tell us?Here we present and describe the detailed thorium distribution in PKT,SPAT,and FHT and provide some information for the origin of asymmetries on the lunar surface.
基金supported by the B-type Strategic Priority Program of the Chinese Academy of Sciences(XDB41000000)the National Natural Science Foundation of China(42373042)+3 种基金the National Key Scientifi c Instrument and Equipment Development Project(2012YQ090229)the Scientifi c Instrument Upgrading Project of Shandong Province(2012SGGZ18)the Key Research Program of the Chinese Academy of Sciences(ZDBS-SSWTLC001)the Program of the Institute of Geology&Geophysics CAS(IGGCAS-201905).
文摘Perchlorate and chlorate are present in various extraterrestrial celestial bodies throughout the solar system,such as Mars,the moon,and asteroids.To date,the origin mechanisms of perchlorate and chlorate on the Martian surface have been well-established;however,relatively little attention has been cast to airless bodies.Here,we experimentally investigated the potential oxidation mechanisms of chloride to chlorate and perchlorate,such as ultraviolet irradiation under H_(2)O-and O_(2)-free conditions and mechanical pulverization processes.Individual minerals,olivine,pyroxene,ilmenite,magnetite,TiO_(2)and anhydrous ferric sulfate,and lunar regolith simulants(low Ti,CLRS-1;high-Ti,CLRS-2)and their metallic iron(Fe^( 0))bearing counterparts were examined.We found that pulverization of dry matrix material-halite mixtures,even in the presence of O_(2),does not necessarily lead to perchlorate and chlorate formation without involving water.Under photocatalytic and H_(2)O and O_(2)-free conditions,olivine and pyroxene can produce oxychlorine(ClO_(x)^(−))species,although the yields were orders of magnitude lower than those under Martian-relevant conditions.Nanophase-Fe^(0)particles in the lunar regolith and the common photocatalyst TiO_(2)can facilitate the ClO_(x)^(−)formation,but their yields were lower than those with olivine.The oxides ilmenite and magnetite did not efficiently contribute to ClO_(x)^(−)production.Our results highlight the critical role of H_(2)O in the oxidation chloride to chlorate and perchlorate,and provide essential insights into the environmental influence on the formation of oxychlorine species on different celestial bodies.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB 41000000)the National Natural Science Foundation of China(42273042 and 41931077)+1 种基金the Youth Innovation Promotion Association,the Chinese Academy of Sciences(2020395)the Guizhou Provincial Science and Technology Projects(QKHJC-ZK[2023]-General 473).
文摘Space weathering is a primary factor in altering the composition and spectral characteristics of surface materials on airless planets.However,current research on space weathering focuses mainly on the Moon and certain types of asteroids.In particular,the impacts of meteoroids and micrometeoroids,radiation from solar wind/solar flares/cosmic rays,and thermal fatigue due to temperature variations are being studied.Space weathering produces various transformation products such as melted glass,amorphous layers,iron particles,vesicles,and solar wind water.These in turn lead to soil maturation,changes in visible and near-infrared reflectance spectra(weakening of characteristic absorption peaks,decreased reflectance,increased near-infrared slope),and alterations in magnetism(related to small iron particles),collectively termed the“lunar model”of space weathering transformation.Compared to the Moon and asteroids,Mercury has unique spatial environmental characteristics,including more intense meteoroid impacts and solar thermal radiation,as well as a weaker particle radiation environment due to the global distribution of its magnetic field.Therefore,the lunar model of space weathering may not apply to Mercury.Previous studies have extensively explored the eff ects of micrometeoroid impacts.Hence,this work focuses on the eff ects of solar-wind particle radiation in global magnetic-field distribution and on the weathering transformation of surface materials on Mercury under prolonged intense solar irradiation.Through the utilization of highvalence state,heavy ion implantation,and vacuum heating simulation experiments,this paper primarily investigates the weathering transformation characteristics of the major mineral components such as anorthite,pyroxene,and olivine on Mercury’s surface and compares them to the weathering transformation model of the Moon.The experimental results indicate that ion implantation at room temperature is insufficient to generate np-Fe^(0)directly but can facilitate its formation,while prolonged exposure to solar thermal radiation on Mercury’s surface can lead directly to the formation of np-Fe^(0).Therefore,intense solar thermal radiation is a crucial component of the unique space weathering transformation process on Mercury’s surface.
文摘The Ideale section(IS)at Montalbano Jonico,Italy,has been approved as a Standard Auxiliary Boundary Stratotype(SABS)for the Global boundary Stratotype Section and Point(GSSP)of the Middle Pleistocene Subseries/Subepoch and Chibanian Stage/Age at the Chiba section,Japan.The proposal was submitted to the voting members of the International Commission on Stratigraphy’s Subcommission on Quaternary Stratigraphy(SQS)on May 4,2023,and following discussions was approved on July 8,2023.The 74 m thick IS continuously spans the Marine Isotope Stage(MIS)20–18 interval,and is part of the longer Montalbano Jonico succession(Basilicata,southern Italy in the Mediterranean region)encompassing MIS 37 to early MIS 16.The IS provides a detailed record based on multiple chronologically well constrained marine and terrestrial proxies,which are particularly useful for outlining the paleoclimatic evolution through the Lower–Middle Pleistocene transition.The high-resolution carbon and oxygen isotope stratigraphy outlines glacial–interglacial and stadial–interstadial phases as well as the sub-millennialscale features of Termination IX and the onset of MIS 19c.The sapropel layer equivalent to insolation cycle 74(784 ka)occurs in early MIS 19c.A prominent peak in the 10Be/9Be record at the MIS 19c–19b transition identifies the low geomagnetic dipole moment associated with the Matuyama–Brunhes boundary interval.Two tephra layers(V3 and V4)relevant to boundary interval are 40Ar/39Ar dated.The V4 layer,occurring at the MIS 19c–b transition and in the middle of the 10Be/9Be peak,has an age of 774.1±0.9 ka,corresponding to the age of the Middle Pleistocene GSSP.A high-resolution alkenone sea-surface temperature and several paleobiological records complement the rich chronological and paleoenvironmental dataset from MIS 20 to the inception of MIS 18.The GSSP boundary interval in the IS is represented from 35.50 to 39.50 m,which corresponds to the interval of the highest values of the 10Be/9Be ratio(~776.35–771.87 ka)and includes the V4 tephra layer and the MIS 19c–MIS 19b transition.This SABS extends the correlation potential of the Middle Pleistocene Subseries/Subepoch GSSP interval to the Mediterranean region.
基金supported by the Key Research Program of the Chinese Academy of Sciences (No. KGZD-EW-603)the National Natural Science Foundation of China (Nos. 41373066, 41403053)the State Scholarship Fund of China (No. 201406410040)
文摘The Chang＇e-3（CE-3） spacecraft successfully landed on one of the youngest mare surfaces on the Moon in December 2013. The Yutu rover carried by CE-3 was equipped with a radar system that could reveal subsurface structures in unprecedented details, which would facilitate understanding regional and global evolutionary history of the Moon. Based on regional geology, cratering scaling, and morphological study, here we quantify the subsurface structures of the landing site using high-resolution orbital and in-situ imagery data. Three layers of lunar regolith, two layers of basalt units, and one layer of ejecta deposits are recognized at the subsurface of the landing site, and their thicknesses are deduced based on the imagery data. These results could serve as essential references for the on-going interpretation of the CE-3 radar data. The ability to validate our theoretical subsurface structure using CE-3 in-situ radar observations will improve the methods for quantifying lunar subsurface structure using crater morphologies and scaling.
基金The study is funded by the National Natural Science Foundation of China(41274027,41274037,41374030 and 41474097)
文摘The 2008 Nura Mw6.7 earthquake occurred in front of the Trans-Alai Range, central Asia. We present Interferometric Synthetic Aperture Radar （InSAR） measurements of its coseismic ground deformation that are available for a major earthquake in the region. Analysis of the InSAR data shows that the earthquake ruptured a secondary fault of the Main Pamir Thrust for about 20 kin. The fault plane striking N46~E and dipping 48~SE is dominated by thrust slip up to 3 m, most of which is confined to the uppermost 2-5 km of the crust, similar to the nearby 1974 MwT.0 Markansu earthquake. The elastic model of interseismic deformation constrained by GPS measurements suggests that the two earthquakes may have resulted from the failures of two high-angle reverse faults that are about 10 km apart and rooted in a locked dScollement at depths of 5-6 kin. The elastic strain is built up by a freely creeping decollement at about 16 mm/a.
基金supported by the National Scientific Foundation of China(Nos.41403052,41773061,41830214)the Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)(Nos.CUGL160402,CUG2017G02)+1 种基金the Lunar and Planetary Science Laboratory,Macao University of Science and Technology Partner Laboratory of Key Laboratory of Lunar and Deep Space Exploration,Chinese Academy of Sciences(Nos.039/2013/A2,121/2017/A3)supported by the National Training Program of Innovation and Entrepreneurship for Undergraduates(No.201610491122)
文摘Over 600 chloride-bearing deposits(chlorides) have been identified on the southern highlands of Mars. These chlorides have critical implications for hydrology and astrobiology: they are indicators of an evaporating super saturated solution, and they could have provided habitat environments for halophilic microorganisms and preserved organic matter. One of the prominent geomorphology characteristics of these chloridebearing regions is the polygonal features within them. The origin of these polygonal features is still in debate. In this study, we have surveyed 153 locations of chlorides using 441 high resolution imaging science experiment(Hi RISE) images to characterize the geomorphology of polygonal features. We identified 3 types of polygonal features of distinct geomorphologic characteristics: fractures, raised ridges, and transitional polygons between fractures and raised ridges. We evaluate previously proposed hypotheses of the formation of the polygonal features, and suggest that the 3 types of polygonal features are indicators of different stages of salt crust formation. Salt crust is usually formed through multiple groundwater activities, and it often occurs in playa environment on Earth. The unique hydrological and astrobiological implications of the chlorides with polygonal features make these deposits of high priority for future landed on and/or sample return exploration missions of Mars.
文摘We review previously published and newly obtained crater size-frequency distributions in the inner solar system. These data indicate that the Moon and the ter- restrial planets have been bombarded by two populations of objects. Population 1, dominating at early times, had nearly the same size distribution as the present-day asteroid belt, and produced heavily cratered surfaces with a complex, multi-sloped crater size-frequency distribution. Population 2, dominating since about 3.8-3.7 Gyr, had the same size distribution as near-Earth objects （NEOs） and a much lower im- pact flux, and produced a crater size distribution characterized by a differential -3 single-slope power law in the crater diameter range 0.02 km to 100 km. Taken to- gether with the results from a large body of work on age-dating of lunar and meteorite samples and theoretical work in solar system dynamics, a plausible interpretation of these data is as follows. The NEO population is the source of Population 2 and it has been in near-steady state over the past ～ 3.7-3.8 Gyr; these objects are derived from the main asteroid belt by size-dependent non-gravitational effects that favor the ejection of smaller asteroids. However, Population 1 was composed of main belt as- teroids ejected from their source region in a size-independent manner, possibly by means of gravitational resonance sweeping during orbit migration of giant planets; this caused the so-called Late Heavy Bombardment （LHB）. The LHB began some time before ～3.9 Gyr, peaked and declined rapidly over the next ～ 100 to 300 Myr, and possibly more slowly from about 3.8-3.7 Gyr to ～2 Gyr. A third crater population （Population S） consisted of secondary impact craters that can dominate the cratering record at small diameters.
基金supported by the National Natural Science Foundation of China (Nos. 41072045, 41102209)the Research Fund for the Doctoral Program of Higher Education (No. 20090145110001)+1 种基金Nondestructive Analysis Technique and Best Analysis Scheme of Lunar Sample (No. TY3Q20110029)China University of Geosciences (Wuhan) GF Special Research Fund (No. CUGXGF0901)
文摘Marius Hills is a volcanic plateau on the nearside of the Moon. It is of great interest for its high concentration of volcanic features, including domes, cones, ridges, and rilles. However, the morphological and chronological characteristics of this plateau were not well studied due to the low resolution of early mission data. This study describes the detailed morphology of the volcanic features using the latest high spatial resolution images of the Terrain Camera （TC） onboard Selene-1 （10 m/pix） and Narrow Angle Camera （NAC） onboard the Lunar Reconnaissance Orbiter （LRO） （0.5 m/pix）. We report here some new structures such as skylights and remnants of lava tubes. We have divided spectrally homogenous areas with Clementine UVVIS data and did crater size frequency distribution （CSFD） measurements with Lunar Orbiter （LO） IV and TC images in every spectral unit. We first report absolute model ages of 1.10 Ga for Marius basalt 1, 1.49 Ga for Fiamsteed basalt, and 1.46 Ga for Schiaparelli Basalt. In addition, we have identified several younger lava events： they are Marius basalt 2 （814 Ma）, medium to low titanium basalt （949 Ma）, and undifferentiated medium titanium basalt （687 Ma）. Finally, we propose a mantle plume scenario for the formation of Marius Hills, which could solve the inconsistency of previous models.
基金supported by a grants from the National Natural Science Foundation of China (Grant Nos. 41864001 and U1831132)Open Fund of State Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University (Grant No. 17P03)+3 种基金Guizhou Normal University Doctoral Research Fundsupported by grants from the Hubei Province Foundation innovation group project (2015CFA011, 2018CFA087)Open Project of Lunar and Planetary Science Laboratory, Macao University of Science and Technology (FDCT 119/2017/A3)Open Fund of Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing (KF201813)
文摘With the increasing precision of the GRAIL gravity field models and topography from LOLA, it is possible to investigate the substructure beneath crater Clavius. An admittance between gravity and topography data is commonly used to estimate selenophysical parameters, including load ratio, crustal thickness and density, and elastic thickness. Not only a surface load, but also a subsurface load is considered in estimation. The algorithm of particle swarm optimization(PSO) with a swarm size of 400 is employed as well.Results indicate that the observed admittance is best-fitted by the modeled admittance based on a spherical shell model, which was proved to be unsatisfactory in the previous study. The best-fitted load ratio f is around-0.194. Such a small load ratio conforms to the direct proportion between the nearly uncompensated topography and its corresponding negative gravity anomaly. It also indicates that a surface load dominates all the loads. Constrained within 2σSTD, a small crustal thickness(～30 km) and a crustal density of ～2587 kg m-3are found, quite close to the results from previous GRAIL research. Considering the well constrained crustal thickness and density, the best-fitted elastic thickness(～7 km) is rational. This result is slightly smaller than the previous study(～12 km). Such difference can be attributed to the difference in crustal density used and the precision of gravity and topography data. Considering that the small difference between the modeled gravity anomaly and observations is quite small, a parameter inversed here could be an indicator of the subsurface structure beneath Clavius.
基金supported by the National Scientific Foundation of China (No. 41773061)the Fundamental Research Funds for the Central Universities,China University of Geosciences (Wuhan) (Nos. CUGL160402, CUG2017G02 and CUGYCJH18-01)
文摘Yardangs are wind-eroded ridges usually observed in arid regions on Earth and other planets. Previous geomorphology studies of terrestrial yardang fields depended on satellite data and limited fieldwork. The geometry measurements of those yardangs based on satellite data are limited to the length, the width, and the spacing between the yardangs; elevations could not be studied due to the relatively low resolution of the satellite acquired elevation data, e.g. digital elevation models(DEMs). However, the elevation information(e.g. heights of the yardang surfaces) and related information(e.g. slope) of the yardangs are critical to understanding the characteristics and evolution of these aeolian features. Here we report a novel approach, using unmanned aerial vehicles(UAVs) to generate centimeterresolution orthomosaics and DEMs for the study of whaleback yardangs in Qaidam Basin, NW China. The ultra-high-resolution data provide new insights into the geomorphology characteristics and evolution of the whaleback yardangs in Qaidam Basin. These centimeter-resolution datasets also have important potential in:(1) high accuracy estimation of erosion volume;(2) modeling in very fine scale of wind dynamics related to yardang formation;(3) detailed comparative planetary geomorphology study for Mars, Venus, and Titan.
基金supported by the National Natural Science Foundation of China(Nos.U2013603 and 52225403)the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(No.2019ZT08G315)the Shenzhen National Science Fund for Distinguished Young Scholars(No.RCJC20210706091948015).
文摘With the increasing scarcity of Earth’s resources and the development of space science and technology,the exploration, development, and utilization of deep space-specific material resources(minerals, water ice, volatile compounds, etc.) are not only important to supplement the resources and reserves on Earth but also provide a material foundation for establishing extraterrestrial research bases. To achieve large depth in-situ condition-preserved coring(ICP-Coring) in the extreme lunar environment, first, lunar rock simulant was selected(SZU-1), which has a material composition, element distribution, and physical and mechanical properties that are approximately equivalent to those of lunar mare basalt. Second, the influence of the lunar-based in-situ environment on the phase, microstructure, and thermal physical properties(specific heat capacity, thermal conductivity, thermal diffusivity, and thermal expansion coefficient)of SZU-1 was explored and compared with the measured lunar rock data. It was found that in an air atmosphere, low temperature has a more pronounced effect on the relative content of olivine than other temperatures, while in a vacuum atmosphere, the relative contents of olivine and anorthite are significantly affected only at temperatures of approximately-20 and 200 ℃. When the vacuum level is less than100 Pa, the contribution of air conduction can be almost neglected, whereas it becomes dominant above this threshold. Additionally, as the testing temperature increases, the surface of SZU-1 exhibits increased microcracking, fracture opening, and unevenness, while the specific heat capacity, thermal conductivity,and thermal expansion coefficient show nonlinear increases. Conversely, the thermal diffusivity exhibits a nonlinear decreasing trend. The relationship between thermal conductivity, thermal diffusivity, and temperature can be effectively described by an exponential function(R^(2)>0.98). The research results are consistent with previous studies on real lunar rocks. These research findings are expected to be applied in the development of the test and analysis systems of ICP-Coring in a lunar environment and the exploration of the mechanism of machine-rock interaction in the in-situ drilling and coring process.
基金supported by the National Natural Science Foundation of China (41864001 and U1831132)Guizhou Science and Technology Plan Project (Guizhou Science and Technology platform talents [2018]5769)+5 种基金Open Fund of State Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University (Grant No. 17P03)Open Fund of Key Laboratory of Environment Change and Resources Use in Beibu Gulf, Ministry of Education (Guangxi Teachers Education University)Guangxi Key Laboratory of Earth Surface Processes and Intelligent Simulation (Guangxi Teachers Education University, No. 2015K03)Open Fund of Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing (KF201813)Open Fund of Lunar and Planetary Science Laboratory, Macao University of Science and Technology (FDCT 119/2017/A3)Hubei Province Foundation innovation group project (2018CFA087)
文摘The Moscoviense basin is an atypical lunar impact basin with concentric rings of positive and negative gravity anomalies. This basin can provide insights into the inhomogeneous thermal activities across the farside of the Moon. Based on an updated spherical harmonic thin elastic-shell loading model, we used localized admittance analyses to estimate the elastic thickness as well as other associated selenophysical parameters for the Moscoviense basin. The high precision gravity and topography data employed in our estimation were collected by the Gravity Recovery and Interior Laboratory and the Lunar Orbiter Laser Altimeter missions. Our results indicate that the crust-mantle interface is mainly compensated by the prefilling depth rather than the observed surface topography. The results constrained within two standard deviations yielded a small load ratio(~0.168), a best-fit crustal thickness of 36.2 km, and an optimized crustal density of 3159.5 kg m-3. Such large density approaches the density of olivine-rich mantle materials, implying that the excavation of the Mare Moscoviense occurred during a basin-forming impact. The inversed elastic thickness at Mare Moscoviense was around 18 km, lower than the previous results(~60 km) found over Mare basins on the lunar nearside. These results indicate that extreme thermal activity existed during the Moscoviense basin-forming period such as reheating mechanisms from a double-impact process and mare volcanism.
