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Hafnium isotopic disequilibrium during sediment melting and assimilation

C. Zhang1,2,

1State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing, China
2College of Geoscience, China University of Petroleum, Beijing, China

D. Liu1,3,

1State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing, China
3Unconventional Petroleum Research Institute, China University of Petroleum, Beijing, China

X. Zhang4,

4School of Earth Sciences and Gansu Key Laboratory of Mineral Resources in Western China, Lanzhou University, Lanzhou 730000, China

C. Spencer5,6,

5TIGeR (The Institute of Geoscience Research), School of Earth and Planetary Science, Curtin University, Perth, Australia
6Department of Geological Sciences and Geological Engineering, Queen’s University, Kingston, ON, Canada

M. Tang7,

7Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX, USA

J. Zeng1,2,

1State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing, China
2College of Geoscience, China University of Petroleum, Beijing, China

S. Jiang8,

8Energy and Geoscience Institute, University of Utah, Salt Lake City, UT, USA

M. Jolivet9,

9Géosciences Rennes, CNRS — Université Rennes 1, Rennes, France

X. Kong1,2

1State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing, China
2College of Geoscience, China University of Petroleum, Beijing, China

Affiliations  |  Corresponding Author  |  Cite as  |  Funding information

Zhang, C., Liu, D., Zhang, X., Spencer, C., Tang, M., Zeng, J., Jiang, S., Jolivet, M., Kong, X. (2020) Hafnium isotopic disequilibrium during sediment melting and assimilation. Geochem. Persp. Let. 12, 34–39.

National Natural Science Foundation of China (41502209); National Science and Technology Major Project (2016ZX05034-001, 2017ZX05035-002)

Geochemical Perspectives Letters v12  |  doi: 10.7185/geochemlet.2001
Received 01 June 2019  |  Accepted 24 November 2019  |  Published 15 January 2020
Copyright © The Authors

Published by the European Association of Geochemistry
under Creative Commons License CC BY-NC-ND 4.0




Figure 1 (a) εHf(t) versus εNd(t) for SPG in the Chinese Altai calculated based on U-Pb ages of the various plutons. Terrestrial array equations are from Vervoort et al. (2011)

Vervoort, J.D., Plank, T., Prytulak, J. (2011) The Hf–Nd isotopic composition of marine sediments. Geochimica et Cosmochimica Acta 75, 5903–5926.

. (b) Zircon εHf(t) versus zircon δ18O for SPG in the Chinese Altai. Mantle values after Valley et al. (1998)

Valley, J.W., Kinny, P.D., Schulze, D.J., Spicuzza, M.J. (1998) Zircon megacrysts from kimberlite: oxygen isotope variability among mantle melts.     Contributions to Mineralogy and Petrology 133, 1–11.

. Inherited zircons show εHf(t) and δ18O values, indicating a metasedimentary source. Younger magmatic zircons show positive εHf(t) values and similarly high δ18O values, CHUR-chondritic uniform reservoir. (c) εHf(t) versus Zr (µg/g). (d) εNd(t) versus P2O5 (wt. %). Uncertainties of all isotope measurements are internal 2σ.
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Figure 2 Primitive mantle-normalised trace element spider patterns of the studied granites, PAAS and NAS. Normalisation data from Sun and McDonough (1989)

Sun, S.S., McDonough, W.F. (1989) Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. Geological Society, London, Special Publications, 42, 313-345.

. Note the Zr-Hf depletions of the SPG from this study. All the data are listed in Table S-4.
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Figure 3 (a) Compilation of published neodymium and hafnium isotopic compositions of I-type, A-type, and S-type granites (as defined in the figure). Points represent average zircon values from single plutons. References listed in Table S-3. (b) Distance from the terrestrial array (TA) expressed as ΔTA calculated for the three granite groups. Vertical line represents the median of all of the samples and demonstrate an increasing shift towards greater Hf disequilibrium (above the TA) with increasing aluminousity.
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Figure 4 Calculated minimum melt temperature for zircon dissolution as a function of Zr concentration in the protoliths and M value (cation ratio). SPG have M values > 1.1 while I-type granites typically have M values < 1.0. Melt Zr concentration at zircon saturation using the zircon saturation model of Boehnke et al. (2013)

Boehnke, P., Watson, E.B., Trail, D., Harrison, T.M., Schmitt, A.K. (2013) Zircon saturation re-revisited. Chemical Geology 351, 324–334.

.
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