A South Pole–Aitken impact origin of the lunar compositional asymmetry

The formation of the largest and most ancient lunar impact basin, South Pole–Aitken (SPA), was a defining event in the Moon’s evolution. Using numerical simulations, we show that widespread mantle heating from the SPA impact can catalyze the formation of the long-lived nearside-farside lunar asymmet...

Full description

Bibliographic Details
Published in:Science Advances
Main Authors: Jones, Matt J., Evans, Alexander J., Johnson, Brandon C., Weller, Matthew B., Andrews-Hanna, Jeffrey C., Tikoo, Sonia M., Keane, James T.
Format: Article in Journal/Newspaper
Language:English
Published: American Association for the Advancement of Science (AAAS) 2022
Subjects:
South pole
Online Access:http://dx.doi.org/10.1126/sciadv.abm8475
https://www.science.org/doi/pdf/10.1126/sciadv.abm8475
Description
Summary:The formation of the largest and most ancient lunar impact basin, South Pole–Aitken (SPA), was a defining event in the Moon’s evolution. Using numerical simulations, we show that widespread mantle heating from the SPA impact can catalyze the formation of the long-lived nearside-farside lunar asymmetry in incompatible elements and surface volcanic deposits, which has remained unexplained since its discovery in the Apollo era. The impact-induced heat drives hemisphere-scale mantle convection, which would sequester Th- and Ti-rich lunar magma ocean cumulates in the nearside hemisphere within a few hundred million years if they remain immediately beneath the lunar crust at the time of the SPA impact. A warm initial upper mantle facilitates generation of a pronounced compositional asymmetry consistent with the observed lunar asymmetry.

Similar Items