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Direct observation of dislocation nucleation in pyrite using combined electron channelling contrast imaging and electron backscatter diffraction
Author(s) -
Rogowitz Anna,
Zaefferer Stefan,
Dubosq Renelle
Publication year - 2018
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/ter.12358
Subject(s) - channelling , electron backscatter diffraction , misorientation , dislocation , nucleation , materials science , crystal (programming language) , crystallography , transmission electron microscopy , grain boundary , condensed matter physics , geology , composite material , microstructure , nanotechnology , chemistry , ion , physics , organic chemistry , computer science , programming language
Crystal‐plastic deformation is one of the main mechanisms that can accommodate large amounts of strain within the lithosphere. Despite the requirement of understanding dislocation nucleation and arrangement, the only accepted method for direct observation of dislocations in geological materials so far is transmission electron microscopy. Herein, we present a study using a combination of electron channelling contrast imaging ( ECCI ) and electron backscatter diffraction ( EBSD ) to visualize and analyse crystal defects in pyrite deforming close to the crystal plastic to brittle transition zone. Structures in focus include (a) dislocation nucleation at crack‐tips and (b) the reactivation of mode I cracks accompanied by the nucleation of dislocations and crystal‐plastic behaviour resulting in the development of complex dislocation structures and low‐angle grain boundaries. EBSD maps reveal an increase in misorientation towards micro‐cracks, consistent with a greater dislocation density along cracks observed by ECCI .