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Heat diffusion in numerically shocked ordinary chondrites and its contribution to shock melting

Moreau, Juulia-Gabrielle and Schwinger, Sabrina (2021) Heat diffusion in numerically shocked ordinary chondrites and its contribution to shock melting. Physics of the Earth and Planetary Interiors, 310, p. 106630. Elsevier. doi: 10.1016/j.pepi.2020.106630. ISSN 0031-9201.

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Official URL: https://www.sciencedirect.com/science/article/pii/S0031920120303903

Abstract

High pressure shock metamorphism in ordinary chondrites involves heating and melting of individual phases from shock entropy, pore collapse, frictional heating, and heat transfer. Numerical models using shock physics codes have recently been used to comprehend the mechanism of shock heating and melting in multiphase mesoscale models. Such models suggest that the formation of sulfide and metal melt veins in ordinary chondrites (shock-darkening) can be explained by preferential heating and melting of iron and iron sulfides during shock. However, those models usually dismissed heat transfer between heterogeneously shock heated phases. This leads to an underestimation of the degree of melting in phases that experienced low degrees of shock heating (e.g. iron metal) but are in direct contact with strongly shock heated phases (e.g. iron sulfides). In our study, we imple-mented a finite difference 2-D heat diffusion code to model heat diffusion among neighboring grains in shock heated multiphase meshes that represent typical textural relations of silicate, sulfide and metal grains in ordinary chondrites. Post-shock temperature maps for each textural model were calculated using the iSALE shock physics code and used as input for the diffusion code. We find that heat diffusion, not initial shock heating, is the principal cause for heating and melting of metals in eutectic contact with iron sulfides at ~50 GPa of pressure. In addition we study the effects of iron and troilite grain sizes, shock pressures and pre-shock porosities of the silicate matrix, and discuss the preservation of melt allowing melt migration in shock-darkened meteorites and the observation of metal-silicate intermixed melting. With our work, we demonstrate that the consideration of heat diffusion during and after shock is crucial for a better understanding of melting features in both experi-mentally and naturally shocked ordinary chondrites.

Item URL in elib:https://elib.dlr.de/140186/
Document Type:Article
Title:Heat diffusion in numerically shocked ordinary chondrites and its contribution to shock melting
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Moreau, Juulia-GabrielleDepartment of Geosciences and Geography, University of Helsinki, Finland; Institute of Ecology and Earth Sciences, Department of Geology, University of Tartu, EstoniaUNSPECIFIED
Schwinger, SabrinaSabrina.Schwinger (at) dlr.deUNSPECIFIED
Date:January 2021
Journal or Publication Title:Physics of the Earth and Planetary Interiors
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:310
DOI :10.1016/j.pepi.2020.106630
Page Range:p. 106630
Publisher:Elsevier
ISSN:0031-9201
Status:Published
Keywords:shock effects, impacts, heat diffusion, shock melting, ordinary chondrites
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Space Exploration
DLR - Research theme (Project):R - Exploration of the Solar System
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Planetary Physics
Deposited By: Schwinger, Sabrina
Deposited On:11 Jan 2021 13:05
Last Modified:11 Jan 2021 13:05

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