BIROn - Birkbeck Institutional Research Online

    Assessing the survivability of biomarkers within terrestrial material impacting the lunar surface

    Halim, Samuel H. and Crawford, Ian and Collins, G.S. and Joy, K,H, and Davison, T.M. (2020) Assessing the survivability of biomarkers within terrestrial material impacting the lunar surface. Icarus , ISSN 0019-1035. (In Press)

    [img] Text
    32770.pdf - Author's Accepted Manuscript
    Restricted to Repository staff only
    Available under License Creative Commons Attribution Non-commercial No Derivatives.

    Download (2MB) | Request a copy

    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.

    Metadata

    Item Type: Article
    Keyword(s) / Subject(s): Moon, surface, Impact-processes, Cratering, Meteorites, Biomarkers
    School: School of Science > Earth and Planetary Sciences
    Depositing User: Administrator
    Date Deposited: 03 Aug 2020 10:16
    Last Modified: 05 Aug 2020 05:52
    URI: https://eprints.bbk.ac.uk/id/eprint/32770

    Statistics

    Downloads
    Activity Overview
    0Downloads
    29Hits

    Additional statistics are available via IRStats2.

    Archive Staff Only (login required)

    Edit/View Item Edit/View Item