Crust stratigraphy and heterogeneities of the first kilometers at the dichotomy boundary in western Elysium Planitia and implications for InSight lander

Pan, Lu; Quantin‐Nataf, Cathy; Tauzin, Benoît; Michaut, Chloé; Golombek, M. P.; Lognonné, Philippe; Grindrod, Peter M.; Langlais, B.; Гудкова, Т. В.; Степанова, И. Э.; Rodríguez, S.; Lucas, Antoine

doi:10.1016/j.icarus.2019.113511

Cited by 50 publications

(74 citation statements)

References 87 publications

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“…Regional geologic mapping identified this portion of western Elysium Planitia as part of the Early Hesperian transitional unit (eHt), comprised of layered volcanic and/or sedimentary materials (Tanaka et al, 2014). Pre‐ and post‐landing geomorphic, thermal, and mineralogic observations support a basaltic volcanic origin (Golombek et al, 2018; Pan et al, 2019). North‐south trending wrinkle ridges, 10‐ to 100‐m‐diameter (order of magnitude) rocky ejecta craters (RECs), degraded lobate flow margins, and spectra consistent with mafic minerals at shallow depths (exposed in fresh crater walls), have all been identified within the immediate region surrounding and including the landing ellipse (Golombek et al, 2018; Pan et al, 2019).…”

Section: Introductionmentioning

confidence: 93%

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

et al. 2020

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The InSight mission to Mars landed within Homestead hollow on an Early Amazonian lava plain. The hollow is a 27-m-diameter, 0.3-m-deep quasi-circular depression that shares morphologic and sedimentologic characteristics to degraded impact craters. Unlike the intercrater plains outside of the hollow, the interior lacks cobbles and is dominated by loose sand, granules, and pebbles. Fresher craters near the landing site exhibit meter-scale bedforms in their ejecta and on their floors due to sediment trapping. The sedimentology of the interior fill of Homestead hollow suggests similar trapping. The hollow falls along a morphologic continuum that requires low rates of rim degradation and fill. Crater degradation rates (rim erosion plus filling) in the landing site decline nonlinearly through time from 10 −2 to 10 −4 m/Myr as craters evolve to a hollow-like form. Rim erosion rates are lower initially, at 10 −3 m/Myr, but converge with degradation rates to 10 −4 m/Myr. This implies that while filling plays an important role soon after crater formation, it is limited in later stages. Crater statistics indicate that the bulk of the fill occurred in the first 50 Myr for Homestead hollow. The estimated maximum age of the hollow is~400 to 700 Myr. This requires near-zero fill aggradation and long-term soil stability for the bulk of the crater's history. Fill stability manifests in Homestead hollow as a~5-to 10-cm-thick duricrust, formed by exchanges of atmospheric water vapor with soil. The estimated degradation in the hollow requires~2 to 3 m of sedimentary fill beneath the lander. Plain Language Summary The Interior Exploration using Seismic Investigation, Geodesy andHeat Transport (InSight) mission to Mars landed in western Elysium Planitia. The landing site consists of a smooth, flat surface that is unique relative to the surrounding rockier plains. Observations from orbital satellite imagery indicate that InSight landed inside of an almost circular depression in the landscape. Here we evaluate the shape and form of this small circular depression and compare it against nearby degraded impact craters. We conclude that InSight landed inside a very old crater that has filled in with windblown sediment and slope debris from the crater wall. We also estimate that the crater has been sitting on the landscape, experiencing extremely slow degradation, for approximately 400 to 700 Myr. The crater origin for the depression has implications for our understanding of the materials that exist immediately beneath the lander and the results from the two geophysical instruments onboard InSight, the Seismic Experiment for Interior Structure (SEIS) and Heat Flow and Physical Properties Package (HP 3 ).

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Section: Introductionmentioning

confidence: 93%

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

et al. 2020

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“…Furthermore, the smooth plains have been interpreted to be composed of an impact fragmented regolith 3–10 m thick underlain by Hesperian to Early Amazonian basaltic lava flows. This is based on geologic mapping, exposures of scarps, rocky ejecta craters (RECs), CRISM spectra, and the presence of wrinkle ridges (Golombek et al, 2017; Golombek, Grott, et al, 2018; Warner et al, 2017; Pan et al, 2020). Observations of the Gusev cratered plains during the Spirit rover traverse (Grant et al, 2004; Golombek, Crumpler, et al, 2006) also indicate an impact generated regolith about 10 m thick that overlies Hesperian basalt flows.…”

Section: General Predictionsmentioning

confidence: 99%

“…Journal of Geophysical Research: Planets water or ice within 5 m of the surface (Golombek et al, 2017). In addition, there is no evidence that surface materials have high concentrations of water bearing minerals (e.g., Pan & Quantin, 2018;Pan et al, 2020). In fact, the formation of a fragmented regolith overlying basalt flows was viewed as a barrier for the generation of special regions and no subsurface reflectors were identified in SHARAD data (e.g., Putzig et al, 2017).…”

Section: 1029/2020je006502mentioning

confidence: 99%

Assessment of InSight Landing Site Predictions

et al. 2020

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Comprehensive analysis of remote sensing data used to select the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) landing site correctly predicted the atmospheric temperature and pressure profile during entry and descent, the safe landing surface, and the geologic setting of the site. The smooth plains upon which the InSight landing site is located were accurately predicted to be generally similar to the Mars Exploration Rover Spirit landing site with relatively low rock abundance, low slopes, and a moderately dusty surface with a 3–10 m impact fragmented regolith over Hesperian to Early Amazonian basaltic lava flows. The deceleration profile and surface pressure encountered by the spacecraft during entry, descent, and landing compared well (within 1σ) of the envelope of modeled temperature profiles and the expected surface pressure. Orbital estimates of thermal inertia are similar to surface radiometer measurements, and materials at the surface are dominated by poorly consolidated sand as expected. Thin coatings of bright atmospheric dust on the surface were as indicated by orbital albedo and dust cover index measurements. Orbital estimates of rock abundance from shadow measurements in high‐resolution images and thermal differencing indicated very low rock abundance and surface counts show 1–4% area covered by rocks. Slopes at 100 to 5 m length scale measured from orbital topographic and radar data correctly indicated a surface comparably smooth and flat as the two smoothest landing sites (Opportunity and Phoenix). Thermal inertia and radar data indicated the surface would be load bearing as found.

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“…InSight landed in Elysium Planitia near the boundary of Mars's crustal dichotomy. From orbital data, InSight appears to have landed on a plain of early‐Amazonian or late‐Hesperian (∼3.0 Ga) lava flows 200–300 m thick, which overlie sedimentary rocks of Noachian age (∼3.7–4.1 Ga) (Pan et al., 2020). The sediments themselves may overlie altered basaltic rocks that are compacted at depth (Smrekar et al., 2019).…”

Section: Effects Of Geologymentioning

confidence: 99%

Constraints on Thermal History of Mars From Depth of Pore Closure Below InSight

Gyalay

Nimmo

Plesa

et al. 2020

Geophysical Research Letters

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Planetary crusts undergo viscous closure of pores at depth; if the thickness of this porous layer can be measured, constraints on crustal thermal evolution can be derived. We apply a pore closure model developed for the Moon to Mars and take into account the geological processes that may alter the depth of this transition region. If the 8–11 km deep discontinuity in seismic wave speed detected by the InSight lander marks the base of the porous layer, the heat flux at the time the porosity was created must have exceed 60 mW m−2, probably indicating a time prior to 4 Ga.

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Crust stratigraphy and heterogeneities of the first kilometers at the dichotomy boundary in western Elysium Planitia and implications for InSight lander

Cited by 50 publications

References 87 publications

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

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

Assessment of InSight Landing Site Predictions

Constraints on Thermal History of Mars From Depth of Pore Closure Below InSight

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