206 Strain and Displacement: Patterns, Gradients, Partitioning, and Reconstructions

This session aims to bring together researchers from structure-related disciplines to facilitate discussions of approaches that inform our understanding of strain and displacement. We welcome contributions from observations, experiments, theory, and modeling that characterize deformation from micro to tectonic scales.

Tuesday, 21 October 2025
1:30 PM - 5:30 PM
HBGCC, 217C

Some important microstructural processes in quartz that facilitate strain

Paper number: 206-0
Program: Technical Sessions
Time: 1:30 PM – 1:50 PM

Authors

Abstract

Owing to its abundance in continental crust, the mechanical and chemical behavior of quartz plays a big role in facilitating strain. Of interest, quartz exhibits large elastic and thermal anisotropy, is easily dissolved when in contact with phyllosilicates, and is the only common mineral that undergoes a phase change at crustal temperature and pressure conditions. Recent work also shows that grain boundary migration in quartz during dynamic recrystallization is strongly influenced by dislocation walls that intersect the grain boundaries. In this presentation we will explore the following in relation to strain: microcracking associated with change from the beta to the alpha phase, mass transfer associated with the formation of crenulation cleavage, and the influence of dislocation walls on the heterogeneous migration of grain boundaries. Heterogeneous migration of grain boundaries leads to “roughening” or lengthening of grain perimeters, thus affecting the balance between dislocation energy and grain boundary energy. Using experimentally deformed samples, we show that the perimeter-area fractal dimension (the slope of the log-log relationship between perimeter and diameter) of quartz grains deformed in dislocation creep strongly correlates with applied differential stress, providing a new piezometer and a novel link between stress, strain, and microstructural processes.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-413351

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