Complex Crater Formation by Oblique Impacts on the Earth and Moon

Davison, T. M.; Collins, G. S.

doi:10.1029/2022gl101117

Cited by 10 publications

(5 citation statements)

References 41 publications

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“…The crater is distinctly asymmetric with steeper rim faults and a deeper ring syncline in the northeast in comparison to the southwest. This is consistent with results of oblique impact experiments 24 , impact simulations 25 , and observations of con rmed impact craters 26 , which show that a deeper annular moat would be expected in the uprange direction. However, inherited and reactivated normal (or transtensional faults) add complexity to the interpretation, as the inherited structural fabric has a strong NW-SE fault orientation.…”

Section: Reconstructing Impact Anglesupporting

confidence: 90%

3D anatomy of the Cretaceous-Paleogene age Nadir Crater

Nicholson,

Powell,

Gulick

et al. 2024

Preprint

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The Nadir Crater offshore West Africa is a recently proposed near K-Pg impact structure identified on 2D seismic. Here we present 3D seismic data that image this crater in exceptional detail, unprecedented for any such structure, which demonstrates beyond reasonable doubt that the crater-forming mechanism was a hypervelocity impact. Seismic mapping reveals a near-circular crater rim of 9.2 km and an outer brim of ~23 km diameter defined by concentric normal faults. An extended damage zone is evident across the region, well beyond the perceived limit of subsurface deformation for impact craters, except in a ‘sheltered zone’ to the east. The seabed shows evidence for widespread liquefaction because of seismic shaking and scars and gullies formed by tsunami wave propagation and resurge. Deformation within the ~425 m high stratigraphic uplift and annular moat allow us to reconstruct the evolution of the crater, with radial thrusts at the periphery of the uplift suggesting a low-angle impact from the east. Structural relationships allow us to reconstruct the deformation processes during the crater modification stage, with the central uplift forming first, followed by centripetal flow of surrounding sediments into the evacuated crater floor in the seconds to minutes after impact.

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Section: Reconstructing Impact Anglesupporting

confidence: 90%

3D anatomy of the Cretaceous-Paleogene age Nadir Crater

Nicholson,

Powell,

Gulick

et al. 2024

Preprint

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“…Crater-forming impacts involve high energy release with high temperatures and pressures across short time scales. Their structural and morphological characteristics depend on several interconnected factors, including the impact dynamics, target, and bolide characteristics and formations mechanisms, all of which are reflected in the wide range of craters observed in planetary bodies [51,52]. Note that Figure 7 also includes the reconstructed profiles from Collins et al [19], which showed that their reconstructed profiles were consistently above the actual postimpact topography observed in the field.…”

Section: Crater Surface Topographymentioning

confidence: 85%

“…Such difference might be caused by the difference in the mechanical premises between DEM and hydrocode-based modeling methods. Determining the impact angle and trajectory has been investigated from field observations and numerical simulations [13,18,19,51]. Crater-forming impacts involve high energy release with high temperatures and pressures across short time scales.…”

Section: Crater Surface Topographymentioning

confidence: 99%

Numerical Modeling of an Asteroid Impact on Earth: Matching Field Observations at the Chicxulub Crater Using the Distinct Element Method (DEM)

Duong¹,

Hernawan

Medina-Cetina

et al. 2023

Geosciences

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In recent years, an international consortium of research organizations conducted investigations at the Chicxulub Crater in Yucatan, Mexico, to better understand the crater’s formation mechanisms and the effects produced by the impact of the asteroid that is hypothesized to have caused one of the major life extinctions on Earth. This study aims to reproduce the asteroid’s impact mechanics by matching computer simulations obtained with the use of the distinct element method (DEM) against the latest topographic data observed across the crater footprint. A 2D model was formulated using ITASCA’s PFC2D software to reproduce the asteroid’s impact on Earth. The model ground conditions prior to impact were replicated based on available geological and geophysical field information. Also, the proposed DEM model configuration was designed to reproduce a far-field effect to ascertain the energy dissipation of the asteroid’s impact at the model’s boundaries. Impact conditions of the asteroid were defined based on previous asteroid impact investigations. A parametric analysis including the asteroid’s impact angle and the asteroid’s impact velocity was conducted to assess their influence on the crater formation process. Results of the simulations included the final crater topography and stratigraphy, stress profiles, contact force chains, and velocity fields. Numerical simulations showed that both the asteroid velocity and impact inclination play a major role in the crater formation process, and that the use of DEM provides interesting insights into impact crater formation.

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“…Note that oblique impacts in the three-dimensional simulations may enlarge the melt volume within the methane clathrate layer (Wakita et al 2019(Wakita et al , 2022a. Nevertheless, their change in the topography might be modest (Davison & Collins 2022). As we focus on the crater size (diameter and depth), the fate of impact ejecta is also beyond the scope of our work.…”

Section: Discussionmentioning

confidence: 99%

Modeling the Formation of Selk Impact Crater on Titan: Implications for Dragonfly

et al. 2023

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Selk crater is an ∼80 km diameter impact crater on the Saturnian icy satellite Titan. Melt pools associated with impact craters like Selk provide environments where liquid water and organics can mix and produce biomolecules like amino acids. It is partly for this reason that the Selk region has been selected as the area that NASA’s Dragonfly mission will explore and address one of its primary goals: to search for biological signatures on Titan. Here we simulate Selk-sized impact craters on Titan to better understand the formation of Selk and its melt pool. We consider several structures for the icy target material by changing the thickness of the methane clathrate layer, which has a substantial effect on the target thermal structure and crater formation. Our numerical results show that a 4 km diameter impactor produces a Selk-sized crater when 5–15 km thick methane clathrate layers are considered. We confirm the production of melt pools in these cases and find that the melt volumes are similar regardless of methane clathrate layer thickness. The distribution of the melted material, however, is sensitive to the thickness of the methane clathrate layer. In the case of a 10–15 km thick methane clathrate layer, the melt pool appears as a torus-like shape that is a few kilometers deep, and as a shallower layer in the case of a 5 km thick clathrate layer. Melt pools of this thickness may take tens of thousands of years to freeze, allowing more time for complex organics to form.

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Complex Crater Formation by Oblique Impacts on the Earth and Moon

Cited by 10 publications

References 41 publications

3D anatomy of the Cretaceous-Paleogene age Nadir Crater

3D anatomy of the Cretaceous-Paleogene age Nadir Crater

Numerical Modeling of an Asteroid Impact on Earth: Matching Field Observations at the Chicxulub Crater Using the Distinct Element Method (DEM)

Modeling the Formation of Selk Impact Crater on Titan: Implications for Dragonfly

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