Assessing the survivability of biomarkers within terrestrial material impacting the lunar surface
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Author(s)
Halim, SH
Crawford, IA
Collins, GS
Joy, KH
Davison, TM
Type
Journal Article
Abstract
The history of organic and biological markers (biomarkers) on the Earth is effectively non-existent in the geological record >3.8 Ga ago. Here, we investigate the potential for terrestrial material (i.e., terrestrial meteorites) to be transferred to the Moon by a large impact on Earth and subsequently survive impact with the lunar surface, using the iSALE shock physics code. Three-dimensional impact simulations show that a typical basin-forming impact on Earth can eject solid fragments equivalent to ~10−3 of an impactor mass at speeds sufficient to transfer from Earth to the Moon. Previous modelling of meteorite survivability has relied heavily upon the assumption that peak-shock pressures can be used as a proxy for gauging survival of projectiles and their possible biomarker constituents. Here, we show the importance of considering both pressure and temperature within the projectile, and the inclusion of both shock and shear heating, in assessing biomarker survival. Assuming that they survive launch from Earth, we show that some biomarker molecules within terrestrial meteorites are likely to survive impact with the Moon, especially at the lower end of the range of typical impact velocities for terrestrial meteorites (2.5 km s−1). The survival of larger biomarkers (e.g., microfossils) is also assessed, and we find limited, but significant, survival for low impact velocity and high target porosity scenarios. Thermal degradation of biomarkers shortly after impact depends heavily upon where the projectile material lands, whether it is buried or remains on the surface, and the related cooling timescales. Comparing sandstone and limestone projectiles shows similar temperature and pressure profiles for the same impact velocities, with limestone providing slightly more favourable conditions for biomarker survival.
Date Issued
2021-01-15
Online Publication Date
2020-09-01T10:23:08Z
Date Acceptance
2020-07-31
ISSN
0019-1035
Publisher
Elsevier BV
Start Page
1
End Page
15
Journal / Book Title
Icarus
Volume
354
Copyright Statement
© 2020 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license
Sponsor
Science and Technology Facilities Council (STFC)
Identifier
https://www.sciencedirect.com/science/article/pii/S0019103520303870?via%3Dihub
Grant Number
ST/S000615/1
Subjects
0201 Astronomical and Space Sciences
0402 Geochemistry
0404 Geophysics
Astronomy & Astrophysics
Publication Status
Published online
Article Number
114026
Date Publish Online
2020-08-06