首页|Hf isotopic fingerprinting of geodynamic settings: Integrating isotopes and numerical models

Hf isotopic fingerprinting of geodynamic settings: Integrating isotopes and numerical models

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  • NSTL
  • Elsevier
Hf isotopes have proven invaluable in understanding the evolution of Earth's crust-mantle system, but their use in reconstructing tectonic environments, in many cases, remains equivocal. In this study, we introduce a new approach to predict the Hf isotopic evolutionary pattern for rifting and collision based on the integration of numerical models and Hf-176/Hf-1(77) isotopes. The geodynamic numerical models allow us to estimate the proportion of juvenile material added to the crust through time. On the basis of this proportion, we calculate changing Hf-176/Hf-1(77) ratios using mixing models. Predicted Hf isotopic patterns generated through this numerical approach imply that juvenile signals are observed during back-arc extension, whereas evolved signatures dominate collisional settings. We use this novel modeling approach in the case study region of the Halls Creek Orogen to elucidate its tectonic setting through time. In addition, the geochemical features of magmatic rocks in the case study region imply partial melting of a sub-arc mantle wedge with magma-crust interaction on ascent in a convergent margin setting. The links between predicted Hf isotopic evolution, geodynamic numerical models, whole rock geochemistry and measured zircon Hf isotopic evolution trend resolve three discrete stages in the tectonomagmatic development of the Halls Creek Orogen: (1) oceanic crust subduction; (2) back-arc formation with addition of juvenile mantle input; and (3) docking of the North Australian and Kimberley cratons resulting in the development of mixed-source magmatism formed in a collisional setting. We provide a new method to validate geodynamic models with isotopic datasets, which should lead to more rigorous understanding of crustal evolution. (C) 2019 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

Lu-HfTectonicsNumerical modelingHalls Creek OrogenPaleoproterozoic

Kohanpour, Fariba、Kirkland, Christopher L.、Gorczyk, Weronika、Occhipinti, Sandra、Lindsay, Mark D.、Mole, David、Le Vaillant, Margaux

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Univ Western Australia, Ctr Explorat Targeting, Sch Earth Sci, 35 Stirling Highway, Crawley, WA 6009, Australia

Curtin Univ, Ctr Explorat Targeting Curtin Node, Sch Earth & Planetary Sci, GPO Box U1987, Perth, WA 6845, Australia

Commonwealth Sci & Ind Res Org CSIRO Mineral Reso, 26 Dick Perry Ave, Kensington, WA 6151, Australia

2019

10.1016/j.gr.2019.03.017

Gondwana research

Gondwana research

SCI
ISSN：1342-937X
年,卷(期)：2019.73
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