Detection and characterization of buried lunar craters with GRAIL data

Sood, Rohan; Chappaz, Loïc; Melosh, H. J.; Howell, Kathleen C.; Milbury, C.; Blair, D. M.; Zuber, M. T.

doi:10.1016/j.icarus.2017.02.013

Cited by 28 publications

(22 citation statements)

References 12 publications

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“…As the diameters of QCMAs from Evans et al (2016) used in this study (less than 200 km) overlap the size range of the central positive Bouguer anomalies for larger basins ; see also Baker et al, 2017), we must also consider the possibility that a fraction of the positive QCMAs could be 10.1029/2017JE005421 Journal of Geophysical Research: Planets central mantle uplifts associated with buried peak-ring basins that predate the basin of interest, as has been suggested by Sood et al (2017) for one of the QCMAs identified by Evans et al (2016). Although central positive Bouguer anomalies of preexisting basins have not been conclusively identified interior to basin excavation cavities, central positive Bouguer anomalies associated with preexisting basins are observed interior to the main rim of superposed basins, as exemplified by the Asperitatis, Orientale SW, and Serenitatis North basins, which are contained at least partially within the outer rings of the Nectaris, Orientale, and Serenitatis basins, respectively .…”

Section: State Of Preservation Of the Surface And Crustmentioning

confidence: 75%

Reexamination of Early Lunar Chronology With GRAIL Data: Terranes, Basins, and Impact Fluxes

et al. 2018

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Flooding of the lunar surface by ancient mare basalts has rendered uncertain the ages of lunar geochemical terranes and several impact basins. Here we combine craters having recognizable surface expressions with craters identified only by their gravitational signatures in Gravity Recovery and Interior Laboratory data to reassess the chronological sequence of lunar impact basins and the ages of major lunar geochemical terranes. Our results indicate that although volcanically flooded regions are deficient in craters with diameters greater than 20 km by more than 50% relative to unflooded regions, craters with diameters greater than 90 km can be readily recognized either by topography or by gravity anomaly. On the basis of the areal density of craters with diameters greater than 90 km we conclude that (1) the Serenitatis basin could be as young as the Imbrium basin; (2) the areal density of craters within the Procellarum KREEP Terrane is significantly lower than that for the South Pole‐Aitken basin and the Feldspathic Highlands Terrane; (3) if the youngest age of final crystallization of the lunar magma ocean is adopted as a lower bound on the age of the Procellarum KREEP Terrane, a minimum age of approximately 4.3 Ga is inferred for ~40% of lunar impact basins, including South Pole‐Aitken; and (4) the flux of impactors capable of forming craters with diameters of at least 90 km decreased substantially through the Nectarian and Imbrian periods.

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Section: State Of Preservation Of the Surface And Crustmentioning

confidence: 75%

Reexamination of Early Lunar Chronology With GRAIL Data: Terranes, Basins, and Impact Fluxes

et al. 2018

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“…Therefore, although we include these entirely buried craters in our database, we will not use them later when estimating mare basalt thicknesses. We note that completely buried craters can also sometimes be identified in the Bouguer gravity anomaly maps (e.g., Evans et al, 2016Evans et al, , 2018Sood et al, 2017;Zhang et al, 2018).…”

Section: Classmentioning

confidence: 82%

“…Though the thicker flows in the mare centers can entirely flood craters of a given size, the thinner flows at the margins can only partially flood the crater. This interpretation is supported by the identification of ghost craters in Bouguer gravity anomaly maps in the central portions of the maria (e.g., Evans et al, , ; Sood et al, ; Zhang et al, ). We also note that the smallest buried craters are distributed uniformly across the mare, whereas larger ones are concentrated along the mare‐highland boundaries.…”

Section: Craters Buried By Mare Basaltsmentioning

confidence: 86%

Thickness of Lunar Mare Basalts: New Results Based on Modeling the Degradation of Partially Buried Craters

Wieczorek

et al. 2019

JGR Planets

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Partially buried craters on the Moon are those craters whose distal ejecta are covered by lava flows and where the crater rim crest still protrudes above the mare plain. Based on the difference in rim heights between a partially buried crater and an unburied crater, previous studies estimated the thicknesses of the lunar mare basalts. However, these studies did not consider the erosion of the crater rim height, which can result in an overestimate in the derived thickness. By using recent high‐resolution topographic data, we report a basalt thickness estimation method based on numerically modeling the topographic degradation of partially buried craters. We identified 661 buried craters over the lunar surface, and their spatial distribution suggests a preferential occurrence along the mare‐highland boundaries. An elevation model of fresh lunar craters was derived, and the topographic diffusion equation was used to model crater degradation. By modeling the formation, degradation, and flooding of partially buried craters, basalt thicknesses were estimated for 41 mare craters whose rims are completely exposed. The resulting mare basalt thicknesses vary from 33 to 455 m, with a median value of 105 m that is 95 m smaller than that derived when not considering crater degradation. The estimated eruption rate of lunar mare basalts is found to have peaked at 3.4 Ga and then decreased with time, indicating a progressive cooling of the lunar interior. As a by‐product from the crater degradation model, our results suggest that the topographic diffusivity of lunar craters increases with diameter.

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“…However, the isostatic readjustment of mantle uplift takes a much longer time to reach a state of equilibrium (Kamata et al, ), so the Bouguer gravity anomalies caused by the mantle uplift can still be detected long after the surface topography has vanished. Explanations of the origins of the quasi‐circular Bouguer anomalies (i.e., QCBAs) at ancient impact sites were validated by forward models (Sood et al, ). The diameter of a QCBA can be translated to an original rim‐to‐rim basin size based on empirical size relationship between the central gravity anomaly and the rim‐to‐rim diameter of the impact basin (Baker et al, ; Baker, Head, Schon, et al, ).…”

Section: Introductionmentioning

confidence: 99%

“…The diameter of a QCBA can be translated to an original rim‐to‐rim basin size based on empirical size relationship between the central gravity anomaly and the rim‐to‐rim diameter of the impact basin (Baker et al, ; Baker, Head, Schon, et al, ). Based on the remnant Bouguer gravity anomalies in ancient degraded impact basins, QCBAs have been detected on the Moon (Evans et al, ; Featherstone et al, ; Sood et al, ) and Mars (Edgar & Frey, ) but not for the innermost terrestrial planet, Mercury.…”

Section: Introductionmentioning

confidence: 99%

Buried Impact Features on Mercury as Revealed by Gravity Data

et al. 2018

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Gravity data provide information about the internal mass distribution of celestial bodies. The latest gravity field model of Mercury, HgM007, has a higher spatial resolution than previously published gravity models, allowing smaller crustal structures to be resolved. In this study, a global free-air gravity anomaly grid of Mercury was derived from the HgM007 gravity model using the spherical expansion method, and a Bouguer anomaly map was calculated based on the free-air gravity and topography data. We used this gravity model to search for quasi-circular Bouguer anomalies (QCBAs) larger than ∼ 109 km in diameter within the Northern Smooth Plains (NSP) of Mercury, where the resolution of the gravity data is the highest. Assuming that these QCBAs were correlated with mantle uplifts caused by ancient buried impact structures, we applied the prism rectangular shape model and the Markov chain Monte Carlo inversion method to determine the subsurface structure of these QCBAs. Four ancient buried basins, not clearly visible in the surface topography, were detected. We estimated the crustal thickness ratios and original rim-to-rim diameters for these four impact basins, based on empirical cratering scaling laws, finding that the thickness of the infill lava within the NSP might be 5 times larger than previously believed and the ancient terrain beneath the NSP might be older than previously thought.Plain Language Summary Impact basins are generally characterized by two or more concentric rings in the topography. The mass concentration beneath it make impact basins always characterized with gravity high in a gravity anomaly map. The subsurface mass concentration structures take a long time to reach the equilibrium state. Therefore, the gravity data can be used to identify buried impact basins in terrestrial planets. In our work we used a novel Mercury gravity field model and digital elevation model to produce a topography-corrected gravity map. By means of gravity inversion we located four buried impact basins with no topography features. We suggested that surfaces in these buried basins are more ancient than previously thought.

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Detection and characterization of buried lunar craters with GRAIL data

Cited by 28 publications

References 12 publications

Reexamination of Early Lunar Chronology With GRAIL Data: Terranes, Basins, and Impact Fluxes

Reexamination of Early Lunar Chronology With GRAIL Data: Terranes, Basins, and Impact Fluxes

Thickness of Lunar Mare Basalts: New Results Based on Modeling the Degradation of Partially Buried Craters

Buried Impact Features on Mercury as Revealed by Gravity Data

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