Dislocations in minerals: Fast-diffusion pathways or trace-element traps?
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Dislocations in minerals : Fast-diffusion pathways or trace-element traps? / Verberne, Rick; Reddy, Steven M.; Saxey, David W.; Fougerouse, Denis; Rickard, William D. A.; Quadir, Zakaria; Evans, Noreen J.; Clark, Chris.
In: Earth and Planetary Science Letters, Vol. 584, 117517, 2022.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Dislocations in minerals
T2 - Fast-diffusion pathways or trace-element traps?
AU - Verberne, Rick
AU - Reddy, Steven M.
AU - Saxey, David W.
AU - Fougerouse, Denis
AU - Rickard, William D. A.
AU - Quadir, Zakaria
AU - Evans, Noreen J.
AU - Clark, Chris
N1 - Publisher Copyright: © 2022 Elsevier B.V.
PY - 2022
Y1 - 2022
N2 - Element mobility is a critical component in all geological processes and understanding the mechanisms responsible for element mobility in minerals is a fundamental requirement for many geochemical and geochronological applications. Volume diffusion of elements is a commonly assumed process. However, linear defects (dislocations) are an essential component of the high-temperature creep of minerals. These defects are commonly inferred to form fast-diffusion pathways along which trace elements can more rapidly migrate. In contrast, dislocations in minerals are also energetically favourable sites of trace element segregation, which counters the notion that they enhance bulk diffusion rates by a pipe diffusion mechanism. In this paper we characterize the trace-element composition of dislocations on twin boundaries in rutile by combining atom probe tomography with transmission electron microscopy. First, morphology and correlative microstructural data are used to demonstrate that the linear compositional features in the atom probe tomography dataset represent dislocations. Assessment of dislocation composition indicates that segregation is trace element specific. The data show that dislocations in rutile act as both, fast-diffusion pathway and trace-element traps which potentially leads to erroneous estimations of the composition.
AB - Element mobility is a critical component in all geological processes and understanding the mechanisms responsible for element mobility in minerals is a fundamental requirement for many geochemical and geochronological applications. Volume diffusion of elements is a commonly assumed process. However, linear defects (dislocations) are an essential component of the high-temperature creep of minerals. These defects are commonly inferred to form fast-diffusion pathways along which trace elements can more rapidly migrate. In contrast, dislocations in minerals are also energetically favourable sites of trace element segregation, which counters the notion that they enhance bulk diffusion rates by a pipe diffusion mechanism. In this paper we characterize the trace-element composition of dislocations on twin boundaries in rutile by combining atom probe tomography with transmission electron microscopy. First, morphology and correlative microstructural data are used to demonstrate that the linear compositional features in the atom probe tomography dataset represent dislocations. Assessment of dislocation composition indicates that segregation is trace element specific. The data show that dislocations in rutile act as both, fast-diffusion pathway and trace-element traps which potentially leads to erroneous estimations of the composition.
KW - atom probe tomography
KW - diffusion
KW - dislocations
KW - twin boundaries
U2 - 10.1016/j.epsl.2022.117517
DO - 10.1016/j.epsl.2022.117517
M3 - Journal article
AN - SCOPUS:85127521692
VL - 584
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
SN - 0012-821X
M1 - 117517
ER -
ID: 315980079