An Impact Crater Origin for the InSight Landing Site at Homestead Hollow, Mars: Implications for Near Surface Stratigraphy, Surface Processes, and Erosion Rates

The Lunar Penetrating Radar (LPR) onboard the Yutu-2 rover from China’s Chang’E-4 (CE-4) mission is used to probe the subsurface structure and the near-surface stratigraphic structure of the lunar regolith on the farside of the Moon. Structural analysis of regolith could provide abundant information on the formation and evolution of the Moon, in which the rock location and property analysis are the key procedures during the interpretation of LPR data. The subsurface velocity of electromagnetic waves is a vital parameter for stratigraphic division, rock location estimates, and calculating the rock properties in the interpretation of LPR data. In this paper, we propose a procedure that combines the regolith rock extraction technique based on local correlation between the two sets of LPR high-frequency channel data and the common offset semblance analysis to determine the velocity from LPR diffraction hyperbola. We consider the heterogeneity of the regolith and derive the relative permittivity distribution based on the rock extraction and semblance analysis. The numerical simulation results show that the procedure is able to obtain the high-precision position and properties of the rock. Furthermore, we apply this procedure to CE-4 LPR data and obtain preferable estimations of the rock locations and the properties of the lunar subsurface regolith.

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Mineralogical and chemical properties inversed from 21-lunar-day VNIS observations taken during the Chang’E-4 mission

Scientific Reports ◽

10.1038/s41598-021-93694-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Qinghong Zeng ◽

Shengbo Chen ◽

Yuanzhi Zhang ◽

Yongling Mu ◽

Rui Dai ◽

...

Keyword(s):

Impact Crater ◽

Near Infrared ◽

Infrared Imaging ◽

Chemical Properties ◽

Landing Site ◽

Radiative Transfer Model ◽

Transfer Model ◽

Chemical Compositions ◽

Impact Melt ◽

And Chemical Properties

AbstractWe report on the mineralogical and chemical properties of materials investigated by the lunar rover Yutu-2, which landed on the Von Kármán crater in the pre-Nectarian South Pole–Aitken (SPA) basin. Yutu-2 carried several scientific payloads, including the Visible and Near-infrared Imaging Spectrometer (VNIS), which is used for mineral identification, offering insights into lunar evolution. We used 86 valid VNIS data for 21 lunar days, with mineral abundance obtained using the Hapke radiative transfer model and sparse unmixing algorithm and chemical compositions empirically estimated. The mineralogical properties of the materials at the Chang’E-4 (CE-4) site referred to as norite/gabbro, based on findings of mineral abundance, indicate that they may be SPA impact melt components excavated by a surrounding impact crater. We find that CE-4 materials are dominated by plagioclase and pyroxene and feature little olivine, with 50 of 86 observations showing higher LCP than HCP in pyroxene. In view of the effects of space weathering, olivine content may be underestimated, with FeO and TiO2 content estimated using the maturity-corrected method. Estimates of chemical content are 7.42–18.82 wt% FeO and 1.48–2.1 wt% TiO2, with a low-medium Mg number (Mg # ~ 55). Olivine-rich materials are not present at the CE-4 landing site, based on the low-medium Mg #. Multi-origin materials at the CE-4 landing site were analyzed with regard to concentrations of FeO and TiO2 content, supporting our conclusion that the materials at CE-4 do not have a single source but rather are likely a mixture of SPA impact melt components excavated by surrounding impact crater and volcanic product ejecta.

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Has erosion globally increased? Long-term erosion rates as a function of climate derived from the impact crater inventory

10.5194/esurf-2018-59 ◽

2018 ◽

Author(s):

Stefan Hergarten ◽

Thomas Kenkmann

Keyword(s):

Time Scale ◽

Impact Crater ◽

Regional Effect ◽

Tropical Zone ◽

Erosion Rates ◽

Continental Scale ◽

River Loads ◽

The Impact

Abstract. Worldwide erosion rates seem to have increased strongly since the beginning of the Quaternary, but there is still discussion about the role of glaciation as a potential driver and even whether the increase is real at all or an artefact due to losses in the long-term sedimentary record. In this study we derive estimates of average erosion rates on the time scale of some tens of million years from the terrestrial impact crater inventory. This approach is completely independent from all other methods to infer erosion rates such as river loads, preserved sediments, cosmogenic nuclides and thermochronometry. Our approach yields average erosion rates as a function of present-day topography and climate. The results confirm that topography accounts for the main part of the huge variation of erosion on Earth, but also identifies a significant systematic dependence on climate in contrast to several previous studies. We found a fivefold increase in erosional efficacy from the cold regimes to the tropical zone and that temperate and arid climates are very similar in this context. Combining our results to a worldwide mean erosion rate we found that erosion rates on the time scale of some tens of million years are at least as high as present-day rates and suggest that glaciation has a rather regional effect with a limited impact at the continental scale.

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A high-resolution simulation of the ocean during the POMME experiment: Mesoscale variability and near surface processes

Journal of Geophysical Research Atmospheres ◽

10.1029/2005jc003389 ◽

2007 ◽

Vol 112 (C4) ◽

Cited By ~ 12

Author(s):

A. Paci ◽

G. Caniaux ◽

H. Giordani ◽

M. Lévy ◽

L. Prieur ◽

...

Keyword(s):

High Resolution ◽

Surface Processes ◽

Mesoscale Variability ◽

Near Surface ◽

Resolution Simulation

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Surface and Near-Surface Atom Dynamics During Low Energy Xe Ion Bombardment of Si and Fcc Surfaces

MRS Proceedings ◽

10.1557/proc-193-301 ◽

1990 ◽

Vol 193 ◽

Cited By ~ 3

Author(s):

M. V. R. Murty ◽

H. S. Lee ◽

Harry A. Atwater

Keyword(s):

Molecular Dynamics ◽

Surface Layer ◽

Ion Bombardment ◽

Low Energy ◽

Surface Processes ◽

Defect Production ◽

Near Surface ◽

Qualitative Nature ◽

Dynamics Simulations ◽

Atom Dynamics

ABSTRACTSurface and near-surface processes have been studied during low energy Xe ion bombardment of Si (001) and fcc surfaces using molecular dynamics simulations. Defect production is enhanced near the surface of smooth Si (001) surfaces with respect to the bulk in the energy range 20–150 eV, but is not confined exclusively to the surface layer. The extent and qualitative nature of bombardment-induced dissociation of small fcc islands on an otherwise smooth fcc (001) surface is found to depend strongly on island cohesive energy.

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Seismic investigations of the Martian near-surface at the InSight landing site

10.5194/egusphere-egu2020-20481 ◽

2020 ◽

Author(s):

Cedric Schmelzbach ◽

Nienke Brinkman ◽

David Sollberger ◽

Sharon Kedar ◽

Matthias Grott ◽

...

Keyword(s):

Deep Structure ◽

Landing Site ◽

P Wave ◽

Mission Design ◽

Normal Operation ◽

Seismic Signals ◽

Martian Surface ◽

Broadband Seismometer ◽

Near Surface ◽

Martian Regolith

The InSight ultra-sensitive broadband seismometer package (SEIS) was installed on the Martian surface with the goal to study the seismicity on Mars and the deep interior of the Planet. A second surface-based instrument, the heat flow and physical properties package HP3, was placed on the Martian ground about 1.1 m away from SEIS. HP3 includes a self-hammering probe called the &#8216;mole&#8217; to measure the heat coming from Mars' interior at shallow depth to reveal the planet's thermal history. While SEIS was designed to study the deep structure of Mars, seismic signals such as the hammering &#8216;noise&#8217; as well as ambient and other instrument-generated vibrations allow us to investigate the shallow subsurface. The resultant near-surface elastic property models provide additional information to interpret the SEIS data and allow extracting unique geotechnical information on the Martian regolith.The seismic signals recorded during HP3 mole operations provide information about the mole attitude and health as well as shed light on the near-surface, despite the fact that the HP3 mole continues to have difficulty penetrating below 40 cm (one mole length). The seismic investigation of the HP3 hammering signals, however, was not originally planned during mission design and hence faced several technical challenges. For example, the anti-aliasing filters of the seismic-data acquisition chain were adapted when recording the mole hammering to allow recovering information above the nominal Nyquist frequency. In addition, the independently operating SEIS, HP3 and lander clocks had to be correlated more frequently than in normal operation to enable high-precision timing.To date, the analysis of the hammering signals allowed us to constrain the bulk P-wave velocity of the volume between the mole tip and SEIS (top 30 cm) to around 120 m/s. This low velocity value is compatible with laboratory tests performed on Martian regolith analogs with a density of around 1500 kg/m3. Furthermore, the SEIS leveling system resonances, seismic recordings of atmospheric pressure signals, HP3 housekeeping data, and imagery provide additional constraints to establish a first seismic model of the shallow (topmost meters) subsurface at the landing site.

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2-way coupling the hydrological land surface model PROMET with the regional climate model MM5

Hydrology and Earth System Sciences ◽

10.5194/hess-17-1705-2013 ◽

2013 ◽

Vol 17 (5) ◽

pp. 1705-1714 ◽

Cited By ~ 21

Author(s):

F. Zabel ◽

W. Mauser

Keyword(s):

Heat Flux ◽

Land Surface ◽

Regional Climate ◽

Surface Processes ◽

Surface Model ◽

Land Surface Processes ◽

Near Surface ◽

Danube Catchment ◽

Simulated Precipitation ◽

The Impact

Abstract. Most land surface hydrological models (LSHMs) consider land surface processes (e.g. soil–plant–atmosphere interactions, lateral water flows, snow and ice) in a spatially detailed manner. The atmosphere is considered as exogenous driver, neglecting feedbacks between the land surface and the atmosphere. On the other hand, regional climate models (RCMs) generally simulate land surface processes through coarse descriptions and spatial scales but include land–atmosphere interactions. What is the impact of the differently applied model physics and spatial resolution of LSHMs on the performance of RCMs? What feedback effects are induced by different land surface models? This study analyses the impact of replacing the land surface module (LSM) within an RCM with a high resolution LSHM. A 2-way coupling approach was applied using the LSHM PROMET (1 × 1 km2) and the atmospheric part of the RCM MM5 (45 × 45 km2). The scaling interface SCALMET is used for down- and upscaling the linear and non-linear fluxes between the model scales. The change in the atmospheric response by MM5 using the LSHM is analysed, and its quality is compared to observations of temperature and precipitation for a 4 yr period from 1996 to 1999 for the Upper Danube catchment. By substituting the Noah-LSM with PROMET, simulated non-bias-corrected near-surface air temperature improves for annual, monthly and daily courses when compared to measurements from 277 meteorological weather stations within the Upper Danube catchment. The mean annual bias was improved from −0.85 to −0.13 K. In particular, the improved afternoon heating from May to September is caused by increased sensible heat flux and decreased latent heat flux as well as more incoming solar radiation in the fully coupled PROMET/MM5 in comparison to the NOAH/MM5 simulation. Triggered by the LSM replacement, precipitation overall is reduced; however simulated precipitation amounts are still of high uncertainty, both spatially and temporally. The distribution of precipitation follows the coarse topography representation in MM5, resulting in a spatial shift of maximum precipitation northwards of the Alps. Consequently, simulation of river runoff inherits precipitation biases from MM5. However, by comparing the water balance, the bias of annual average runoff was improved from 21.2% (NOAH/MM5) to 4.4% (PROMET/MM5) when compared to measurements at the outlet gauge of the Upper Danube watershed in Achleiten.

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