Mechanical properties and recrystallization of quartz in presence of H2O: Combination of cracking, subgrain rotation and dissolution-precipitation processes

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F22%3A10478429" target="_blank" >RIV/00216208:11310/22:10478429 - isvavai.cz</a>

Result on the web

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=iQ_xXPz68w" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=iQ_xXPz68w</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.jsg.2022.104630" target="_blank" >10.1016/j.jsg.2022.104630</a>

Result language

angličtina

Original language name

Mechanical properties and recrystallization of quartz in presence of H2O: Combination of cracking, subgrain rotation and dissolution-precipitation processes

Original language description

Natural quartzite samples, as-is and with 0.1 wt% of added H2O, have been deformed up to ~30% bulk strain in axial shortening experiments with constant strain rate of ~10(-6) s(-1) at 900 °C and 1 GPa, and in strain rate stepping ~10(-5) to ~10(-7) s(-1) at 900 °C and 1-1.5 GPa, in order to investigate the role of H2O in deformation and recrystallization of quartz. H2O-added samples showed ~30 MPa lower mean strengths than as-is samples. Samples weaken slightly after 15% strain with mean flow stresses in the range of 154-227 MPa, and stress exponent (n) values between 1.45 and 2.13. The original quartz grains have been deformed plastically (dislocation glide). Discrete mode I cracks without detectable offset have developed in addition to plastic strain. Deformation was associated with recrystallization of up to 20% of the material in the most deformed parts of the samples. New grains were nucleated by both cracking and subgrain rotation, and were largely reconstituted by H2O-promoted grain boundary migration, related to dissolution-precipitation processes. This reconstitution of material is documented by a change in luminescence to blue, caused by trace elements exchange in quartz structure. The blue luminescence is prominent along healed cracks and high angle grain boundaries while it was not observed along the low angle boundaries formed by subgrain rotation. Compared to the as-is samples, the crack-related recrystallization is more frequent in the H2O-added samples. The low stress exponent values may indicate dissolution-precipitation and grain boundary sliding processes to accommodate incompatibilities at grain boundaries arising from an insufficient number of active slip systems. We suggest that the ubiquitous presence of H2O in nature may promote recrystallization of quartz by combinations of cracking, dislocation glide and creep and dissolution-precipitation processes.

Czech name

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Czech description

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Type

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

CEP classification

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OECD FORD branch

10505 - Geology

Project

—

Continuities

S - Specificky vyzkum na vysokych skolach<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2022

Confidentiality

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

Name of the periodical

Journal of Structural Geology

ISSN

0191-8141

e-ISSN

1873-1201

Volume of the periodical

160

Issue of the periodical within the volume

July

Country of publishing house

GB - UNITED KINGDOM

Number of pages

23

Pages from-to

104630

UT code for WoS article

000812274500001

EID of the result in the Scopus database

2-s2.0-85130951485