Investigating the onset of multi-ring impact basin formation

•Numerical modeling of lunar basin-scale impacts undertaken.•Formation mechanisms for multi-ring basins tested and evaluated.•Equations developed to assess likelihood of multiple-ring formation.•All basins larger than Schrödinger should be capable of forming additional rings.•Thermal conditions infl...

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Bibliographic Details
Published in:Icarus (New York, N.Y. 1962) N.Y. 1962), 2015-11, Vol.261, p.91-99
Main Author: Potter, Ross W.K.
Format: Article
Language:English
Subjects:
Asthenosphere
Basins
Cratering
Formations
Holes
Impact processes
Lithosphere
Lunar surface
Mathematical models
Moon, interior
Moon, surface
Schroedinger equation
Tectonics
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Summary:•Numerical modeling of lunar basin-scale impacts undertaken.•Formation mechanisms for multi-ring basins tested and evaluated.•Equations developed to assess likelihood of multiple-ring formation.•All basins larger than Schrödinger should be capable of forming additional rings.•Thermal conditions influence basin structure when impact energy exceeds Schrödinger’s. Multi-ring basins represent some of the largest, oldest, rarest and, therefore, least understood impact crater structures. Various theories have been put forward to explain their formation; there is currently, however, no consensus. Here, numerical modeling is used to investigate the onset of multi-ring basin formation on the Moon using two thermal profiles suitable for the lunar basin-forming epoch. Various multi-ring basin formation hypotheses are discussed, compared, and evaluated against target deformation and strain distribution in the models, as well as geological and geophysical observations. The mechanism that most closely resembles the numerical models in terms of basin formation and structure, as well as observations, appears to be the ring tectonic theory, whereby ring formation is dependent on transient cavities penetrating entirely through the Moon’s lithosphere into the asthenosphere below. The numerical models suggest that all lunar basins larger than Schrödinger (320km diameter) should be capable of forming multiple rings, as their transient cavities penetrate into the asthenosphere for both thermal profiles. Additionally, the models demonstrate that the target’s thermal profile starts to influence basin formation and structure when impact energy exceeds that of the Schrödinger event.
ISSN:0019-1035
1090-2643
DOI:10.1016/j.icarus.2015.08.009