Numerical modelling of basin-scale impact crater formation
Understanding of basin-scale crater formation is limited; only a few examples of basin-scale craters exist and these are difficult to access. The approach adopted in this research was to numerically model basin-scale impacts with the aim of understanding the basin-forming process and basin structure...
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ftimperialcol:oai:spiral.imperial.ac.uk:10044/1/9322 2023-05-15T18:21:59+02:00 Numerical modelling of basin-scale impact crater formation Potter, Ross William Kerrill Collins, Gareth 2012-03 http://hdl.handle.net/10044/1/9322 https://doi.org/10.25560/9322 eng eng Imperial College London Earth Science and Engineering Thesis or dissertation Doctoral Doctor of Philosophy (PhD) 2012 ftimperialcol https://doi.org/10.25560/9322 2019-11-14T23:38:09Z Understanding of basin-scale crater formation is limited; only a few examples of basin-scale craters exist and these are difficult to access. The approach adopted in this research was to numerically model basin-scale impacts with the aim of understanding the basin-forming process and basin structure. Research was divided into: (1) investigating early stage formation processes (impactor survivability), (2) investigating later stage formation processes (excavation and modification) and basin structure, and (3) constraining an impact scenario for the largest lunar crater, the South Pole-Aitken Basin. Various impact parameters were investigated, quantifying their effect on the basin-forming process. Simulations showed impactor survivability, the fraction of impactor remaining solid during the impact process, greatly increased if the impactor was prolate in shape (vertical length > horizontal length) rather than spherical. Low (≲15 km/s) impact velocities and low impact angles (≲30 ) also noticeably increased survivability. Lunar basin-scale simulations removed a significant volume of crustal material during impact, producing thinner post-impact crustal layers than those suggested by gravity-derived basin data. Most simulations formed large, predominantly mantle, melt pools; inclusion of a steep target thermal gradient and high internal temperatures greatly influenced melt volume production. Differences in crustal thickness between simulations and gravity-derived data could be accounted for by differentiation of the voluminous impact-generated melt pools, predicted by the simulations, into new crustal layers. Assuming differentiation occurs, simulation results were used to predict features such as transient crater size for a suite of lunar basins and tentatively suggest lunar thermal conditions during the basin-forming epoch. Additional simulations concerned the formation of the South Pole-Aitken Basin. By constraining simulation results to geochemical and gravity-derived basin data, a best-fit impact scenario for the South Pole-Aitken Basin was found. Doctoral or Postdoctoral Thesis South pole Imperial College London: Spiral Aitken ENVELOPE(-44.516,-44.516,-60.733,-60.733) South Pole |
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Imperial College London: Spiral |
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ftimperialcol |
language |
English |
description |
Understanding of basin-scale crater formation is limited; only a few examples of basin-scale craters exist and these are difficult to access. The approach adopted in this research was to numerically model basin-scale impacts with the aim of understanding the basin-forming process and basin structure. Research was divided into: (1) investigating early stage formation processes (impactor survivability), (2) investigating later stage formation processes (excavation and modification) and basin structure, and (3) constraining an impact scenario for the largest lunar crater, the South Pole-Aitken Basin. Various impact parameters were investigated, quantifying their effect on the basin-forming process. Simulations showed impactor survivability, the fraction of impactor remaining solid during the impact process, greatly increased if the impactor was prolate in shape (vertical length > horizontal length) rather than spherical. Low (≲15 km/s) impact velocities and low impact angles (≲30 ) also noticeably increased survivability. Lunar basin-scale simulations removed a significant volume of crustal material during impact, producing thinner post-impact crustal layers than those suggested by gravity-derived basin data. Most simulations formed large, predominantly mantle, melt pools; inclusion of a steep target thermal gradient and high internal temperatures greatly influenced melt volume production. Differences in crustal thickness between simulations and gravity-derived data could be accounted for by differentiation of the voluminous impact-generated melt pools, predicted by the simulations, into new crustal layers. Assuming differentiation occurs, simulation results were used to predict features such as transient crater size for a suite of lunar basins and tentatively suggest lunar thermal conditions during the basin-forming epoch. Additional simulations concerned the formation of the South Pole-Aitken Basin. By constraining simulation results to geochemical and gravity-derived basin data, a best-fit impact scenario for the South Pole-Aitken Basin was found. |
author2 |
Collins, Gareth |
format |
Doctoral or Postdoctoral Thesis |
author |
Potter, Ross William Kerrill |
spellingShingle |
Potter, Ross William Kerrill Numerical modelling of basin-scale impact crater formation |
author_facet |
Potter, Ross William Kerrill |
author_sort |
Potter, Ross William Kerrill |
title |
Numerical modelling of basin-scale impact crater formation |
title_short |
Numerical modelling of basin-scale impact crater formation |
title_full |
Numerical modelling of basin-scale impact crater formation |
title_fullStr |
Numerical modelling of basin-scale impact crater formation |
title_full_unstemmed |
Numerical modelling of basin-scale impact crater formation |
title_sort |
numerical modelling of basin-scale impact crater formation |
publisher |
Imperial College London |
publishDate |
2012 |
url |
http://hdl.handle.net/10044/1/9322 https://doi.org/10.25560/9322 |
long_lat |
ENVELOPE(-44.516,-44.516,-60.733,-60.733) |
geographic |
Aitken South Pole |
geographic_facet |
Aitken South Pole |
genre |
South pole |
genre_facet |
South pole |
op_doi |
https://doi.org/10.25560/9322 |
_version_ |
1766201341096493056 |