Shock physics mesoscale modeling of shock stage 5 and 6 in ordinary and enstatite chondrites

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F26722445%3A_____%2F19%3AN0000035" target="_blank" >RIV/26722445:_____/19:N0000035 - isvavai.cz</a>

Alternative codes found

RIV/67985831:_____/19:00509585

Result on the web

<a href="https://www.sciencedirect.com/science/article/pii/S0019103518305888" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0019103518305888</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.icarus.2019.06.004" target="_blank" >10.1016/j.icarus.2019.06.004</a>

Result language

angličtina

Original language name

Shock physics mesoscale modeling of shock stage 5 and 6 in ordinary and enstatite chondrites

Original language description

Shock-darkening, the melting of metals and iron sulfides into a network of veins within silicate grains, altering reflectance spectra of meteorites, was previously studied using shock physics mesoscale modeling. Melting of iron sulfides embedded in olivine was observed at pressures of 40-50 GPa. This pressure range is at the transition between shock stage 5 (C-S5) and 6 (C-S6) of the shock metamorphism classification in ordinary and enstatite chondrites. To better characterize C-S5 and C-S6 with a mesoscale modeling approach and assess post-shock heating and melting, we used multi-phase (i.e. olivine/enstatite, troilite, iron, pores, and plagioclase) meshes with realistic configurations of grains. We carried out a systematic study of shock compression in ordinary and enstatite chondrites at pressures between 30 and 70 GPa. To setup mesoscale sample meshes with realistic silicate, metal, iron sulfide, and open pore shapes, we converted backscattered electron microscope images of three chondrites. The resolved macroporosity in meshes was 3-6%. Transition from shock C-S5 to C-S6 was observed through (1) the melting of troilite above 40 GPa with melt fractions of similar to 0.7-0.9 at 70 GPa, (2) the melting of olivine and iron above 50 GPa with melt fraction of similar to 0.001 and 0.012, respectively, at 70 GPa, and (3) the melting of plagioclase above 30 GPa (melt fraction of 1, at 55 GPa). Post-shock temperatures varied from similar to 540 K at 30 GPa to similar to 1300 K at 70 GPa. We also constructed models with increased porosity up to 15% porosity, producing higher post-shock temperatures (similar to 800 K increase) and melt fractions (similar to 0.12 increase) in olivine. Additionally we constructed a pre-heated model to observe post-shock heating and melting during thermal metamorphism. This model presented similar results (melting) at pressures 10-15 GPa lower compared to the room temperature models. Finally, we demonstrated dependence of post-shock heating and melting on the orientation of open cracks relative to the shock wave front. In conclusion, the modeled melting and post-shock heating of individual phases were mostly consistent with the current shock classification scheme (Stoffler et al., 1991, 2018).

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2019

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Icarus

ISSN

0019-1035

e-ISSN

1090-2643

Volume of the periodical

332

Issue of the periodical within the volume

November

Country of publishing house

US - UNITED STATES

Number of pages

16

Pages from-to

50-65

UT code for WoS article

000478106800005

EID of the result in the Scopus database

2-s2.0-85068442450