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Application of Electron Backscatter Diffraction to Calcite-Twinning Paleopiezometry

Published version
Peer-reviewed

Type

Article

Change log

Authors

Kosiorek, Kamil 

Abstract

jats:pElectron backscatter diffraction (EBSD) was used to determine the orientation of mechanically twinned grains in Carrara marble experimentally deformed to a small strain (≤4%) at room temperature and at a moderate confining pressure (225 MPa). The thicknesses of deformation twins were mostly too small to permit determination of their orientation by EBSD but it proved possible to measure their orientations by calculating possible twin orientations from host grain orientation, then comparing calculated traces to the observed twin traces. The validity of the Turner & Weiss method for principal stress orientations was confirmed, particularly when based on calculation of resolved shear stress. Methods of paleopiezometry based on twinned volume fraction were rejected but a practical approach is explored based on twin density. However, although twin density correlates positively with resolved shear stress, there is intrinsic variability due to unconstrained variables such as non-uniform availability of twin nucleation sites around grain boundaries that imposes a limit on the achievable accuracy of this approach.</jats:p>

Description

Keywords

calcite, deformation twinning, EBSD, paleopiezometry, twin density, crystallographic orientation

Journal Title

GEOSCIENCES

Conference Name

Journal ISSN

2076-3263
2076-3263

Volume Title

Publisher

MDPI AG