title: Deformation-induced trace element redistribution in zircon revealed using atom probe tomography.
abstract: Trace elements diffuse negligible distances through the pristine crystal lattice in minerals: this is a fundamental assumption when using them to decipher geological processes. For example, the reliable use of the mineral zircon (ZrSiO4) as a U-Th-Pb geochronometer and trace element monitor requires minimal radiogenic isotope and trace element mobility. Here, using atom probe tomography, we document the effects of crystal-plastic deformation on atomic-scale elemental distributions in zircon revealing sub-micrometre-scale mechanisms of trace element mobility. Dislocations that move through the lattice accumulate U and other trace elements. Pipe diffusion along dislocation arrays connected to a chemical or structural sink results in continuous removal of selected elements (for example, Pb), even after deformation has ceased. However, in disconnected dislocations, trace elements remain locked. Our findings have important implications for the use of zircon as a geochronometer, and highlight the importance of deformation on trace element redistribution in minerals and engineering materials.
authors: Australian Research Council Centre of Excellence for Core to Crust Fluid Systems/GEMOC, Department of Earth and Planetary Sciences, Macquarie University, Sydney, New South Wales 2109, Australia.
authors: Sandra
authors: S
authors: Piazolo
authors: Australian Centre for Microscopy and Microanalysis, University of Sydney, Sydney, New South Wales 2006, Australia.
authors: Alexandre
authors: A
authors: La Fontaine
authors: Australian Centre for Microscopy and Microanalysis, University of Sydney, Sydney, New South Wales 2006, Australia.
authors: Patrick
authors: P
authors: Trimby
authors: School of Geosciences, Grant Institute, University of Edinburgh, Edinburgh EH9 3JW, UK.
authors: Simon
authors: S
authors: Harley
authors: Australian Centre for Microscopy and Microanalysis, University of Sydney, Sydney, New South Wales 2006, Australia.
authors: Limei
authors: L
authors: Yang
authors: Research School of Earth Sciences, Australian National University, Canberra, Australian Capital Territory 0200, Australia.
authors: Richard
authors: R
authors: Armstrong
authors: Australian Centre for Microscopy and Microanalysis, University of Sydney, Sydney, New South Wales 2006, Australia.
authors: Julie M
authors: JM
authors: Cairney