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

Kód výsledku v 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>

Výsledek na webu

<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>

Jazyk výsledku

angličtina

Název v původním jazyce

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

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

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

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

—

Návaznosti

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

Rok uplatnění

2022

Kód důvěrnosti údajů

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

Název periodika

Journal of Structural Geology

ISSN

0191-8141

e-ISSN

1873-1201

Svazek periodika

160

Číslo periodika v rámci svazku

July

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

23

Strana od-do

104630

Kód UT WoS článku

000812274500001

EID výsledku v databázi Scopus

2-s2.0-85130951485