Shock-darkening in ordinary chondrites : Determination of the pressure-temperature conditions by shock physics mesoscale modeling

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dc.contributor University of Helsinki, Department of Physics en
dc.contributor University of Helsinki, Department of Physics en
dc.contributor.author Moreau, J.
dc.contributor.author Kohout, T.
dc.contributor.author Wüennemann, K.
dc.date.accessioned 2017-11-27T10:11:02Z
dc.date.available 2017-11-27T10:11:02Z
dc.date.issued 2017-11
dc.identifier.citation Moreau , J , Kohout , T & Wüennemann , K 2017 , ' Shock-darkening in ordinary chondrites : Determination of the pressure-temperature conditions by shock physics mesoscale modeling ' , Meteoritics and Planetary Science , vol. 52 , no. 11 , 14388084 , pp. 2375-2390 . https://doi.org/10.1111/maps.12935 en
dc.identifier.issn 1086-9379
dc.identifier.other PURE: 89347889
dc.identifier.other PURE UUID: 30bc9c92-ffab-4fee-821e-239e57c3b6fd
dc.identifier.other WOS: 000414860200006
dc.identifier.other WOS: 000414860200006
dc.identifier.other Scopus: 85033241577
dc.identifier.other ORCID: /0000-0003-4458-3650/work/39201678
dc.identifier.uri http://hdl.handle.net/10138/228800
dc.description.abstract We determined the shock-darkening pressure range in ordinary chondrites using the iSALE shock physics code. We simulated planar shock waves on a mesoscale in a sample layer at different nominal pressures. Iron and troilite grains were resolved in a porous olivine matrix in the sample layer. We used equations of state (Tillotson EoS and ANEOS) and basic strength and thermal properties to describe the material phases. We used Lagrangian tracers to record the peak shock pressures in each material unit. The post-shock temperatures (and the fractions of the tracers experiencing temperatures above the melting point) for each material were estimated after the passage of the shock wave and after the reflections of the shock at grain boundaries in the heterogeneous materials. The results showed that shock-darkening, associated with troilite melt and the onset of olivine melt, happened between 40 and 50GPa with 52GPa being the pressure at which all tracers in the troilite material reach the melting point. We demonstrate the difficulties of shock heating in iron and also the importance of porosity. Material impedances, grain shapes, and the porosity models available in the iSALE code are discussed. We also discuss possible not-shock-related triggers for iron melt. en
dc.format.extent 16
dc.language.iso eng
dc.relation.ispartof Meteoritics and Planetary Science
dc.rights en
dc.subject IMPACT en
dc.subject CHONDRITES en
dc.subject SHOCK en
dc.subject IMPACT MODELS en
dc.subject 115 Astronomy, Space science en
dc.subject 114 Physical sciences en
dc.subject 1171 Geosciences en
dc.title Shock-darkening in ordinary chondrites : Determination of the pressure-temperature conditions by shock physics mesoscale modeling en
dc.type Article
dc.description.version Peer reviewed
dc.identifier.doi https://doi.org/10.1111/maps.12935
dc.type.uri info:eu-repo/semantics/other
dc.type.uri info:eu-repo/semantics/acceptedVersion
dc.contributor.pbl

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