Dislocations in minerals: Fast-diffusion pathways or trace-element traps?
Research output: Contribution to journal › Journal article › Research › peer-review
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.
Original language | English |
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Article number | 117517 |
Journal | Earth and Planetary Science Letters |
Volume | 584 |
Number of pages | 10 |
ISSN | 0012-821X |
DOIs | |
Publication status | Published - 2022 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:
© 2022 Elsevier B.V.
- atom probe tomography, diffusion, dislocations, twin boundaries
Research areas
ID: 315980079