The Apollo peak-ring impact basin: Insights into the structure and evolution of the South Pole-Aitken basin

The 492 km-diameter Apollo impact basin post-dates, and is located at the inner edge of, the similar to 2240 km diameter South Pole-Aitken (SPA) basin, providing an opportunity to assess the SPA substructure and lateral heterogeneity. Gravity Recovery and Interior Laboratory gravity data suggest an...

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Bibliographic Details
Published in:Icarus
Main Authors: Potter, Ross W. K., Head, James W., Guo, Dijun, Liu, Jianzhong, Xiao, Long
Format: Report
Language:English
Published: ACADEMIC PRESS INC ELSEVIER SCIENCE 2018
Subjects:
Astronomy & Astrophysics
Cratering
Impact processes
Moon
surface
interior
SCHRODINGER-BASIN
LUNAR EXPLORATION
ANCIENT VOLCANISM
ORIENTALE BASIN
MISSION CONCEPT
COMPLEX CRATER
ORIGIN
CRUST
ROCK
Aitken
Apollo Peak
South Pole
South pole
Online Access:http://ir.gig.ac.cn/handle/344008/45139
https://doi.org/10.1016/j.icarus.2018.02.007
Description
Summary:The 492 km-diameter Apollo impact basin post-dates, and is located at the inner edge of, the similar to 2240 km diameter South Pole-Aitken (SPA) basin, providing an opportunity to assess the SPA substructure and lateral heterogeneity. Gravity Recovery and Interior Laboratory gravity data suggest an average crustal thickness on the floor of SPA of similar to 20 km and within the Apollo basin of similar to 5 km, yet remote sensing data reveal no conclusive evidence for the presence of exposed mantle material. We use the iSALE shock physics code to model the formation of the Apollo basin and find that the observational data are best fit by the impact of a 40 km diameter body traveling at 15 km/s into 20-40 km thick crustal material. These results strongly suggest that the Apollo impact occurred on ejecta deposits and collapsed crustal material of the SPA basin and could help place constraints on the location, size and geometry of the SPA transient cavity. The peak ring in the interior of Apollo basin is plausibly interpreted to be composed of inwardly collapsed lower crustal material that experienced peak shock pressures in excess of 35 GPa, consistent with remote sensing observations that suggest shocked plagioclase. Proposed robotic and/or human missions to SPA and Apollo would present an excellent opportunity to test the predictions of this work and address many scientific questions about SPA basin evolution and structure. (C) 2018 Elsevier Inc. All rights reserved.

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