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The preservation of fossil biomarkers during meteorite impact events: experimental evidence from biomarker-rich projectiles and target rocks

Parnell, J. and Bowden, S.A. and Lindgren, P. and Burchell, M.J. and Milner, D. and Price, M. and Baldwin, E.C. and Crawford, Ian A. (2010) The preservation of fossil biomarkers during meteorite impact events: experimental evidence from biomarker-rich projectiles and target rocks. Meteoritics & Planetary Science 45 (8), pp. 1340-1358. ISSN 1086-9379.

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Official URL: http://dx.doi.org/10.1111/j.1945-5100.2010.01100.x

Abstract

A Devonian siltstone from Orkney, Scotland, shows survival of biomarkers in high-velocity impact experiments. The biomarkers were detected in ejecta fragments from experiments involving normal incidence of steel projectiles at 5–6 km s−1, and in projectile fragments from impact experiments into sand and water at 2–5 km s−1. The associated peak shock pressures were calculated to be in the range of 110–147 GPa for impacts of the steel projectiles into the siltstone target, and hydrocode simulations are used to show the variation of peak pressure with depth in the target and throughout the finite volume projectiles. Thermally sensitive biomarker ratios, including ratios of hopanoids and steranes, and the methylphenanthrene ratio, showed an increase in thermal maturity in the ejecta, and especially the projectile, fragments. Measurement of absolute concentrations of selected biomarkers indicates that changes in biomarker ratios reflect synthesis of new material rather than selective destruction. Their presence in ejecta and projectile fragments suggests that fossil biomarkers may survive hypervelocity impacts, and that experiments using biomarker-rich rock have high potential for testing survival of organic matter in a range of impact scenarios.

Item Type: Article
School or Research Centre: Birkbeck Schools and Research Centres > School of Science > Earth and Planetary Sciences
Depositing User: Administrator
Date Deposited: 05 Apr 2011 13:39
Last Modified: 17 Apr 2013 12:20
URI: http://eprints.bbk.ac.uk/id/eprint/3253

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