On the occurrence, trace element geochemistry, and crystallization history of zircon from in situ ocean lithosphere

Grimes, C. B.; John, Barbara E.; Cheadle, M. J.; Mazdab, Frank K.; Wooden, Joseph L.; Swapp, Susan M.; Schwartz, Joshua

doi:10.1007/s00410-009-0409-2

Cited by 258 publications

(152 citation statements)

References 83 publications

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“…The zircons are also characterized by the least negative Eu anomaly, lowest Th/U and highest HREE/MREE and HREE/LREE. Interestingly, zircons with composition similar to those in Group 2 were not observed in the database of Grimes et al (2009), in particular because of their pronounced Eu anomaly. Group 3 is represented by a single grain, which has the highest Hf, U, Th, P, Y, REE (minus Eu), Nb, Ta contents and moderate Ti contents.…”

Section: Zircon: Structure Chemical and Isotope Compositionmentioning

confidence: 99%

“…The zircon grains are 100-150 µm in diameter along their z axes. They can be classified as Type 2 grains according to Grimes et al (2009), i.e. subhedral grains showing magmatic, oscillatory and/or sector zoning (Fig.…”

Section: Zircon: Structure Chemical and Isotope Compositionmentioning

confidence: 99%

“…The high concentrations of U, Th, P, Y, REE, Nb, Ta are similar to those of some grains from leucocratic veins analysed in Section 3; however, the grain has higher Hf concentration. Similar grains were analysed and are included in the databases of Grimes et al (2009). O isotopes varied slightly between groups ( Fig.…”

Section: Zircon: Structure Chemical and Isotope Compositionmentioning

confidence: 99%

“…Trace elements were analysed in oceanic zircons from a few localities including over 30 analyses of zircon from ODP Site 735B (Grimes et al 2009). Another dataset includes zircons from a felsic vein intruding oxide gabbro, the sample of which was dredged during Leg 31 (Schwartz et al 2010).…”

Section: Zircon: Comparison With Other Datasetsmentioning

confidence: 99%

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Zircon record of fractionation, hydrous partial melting and thermal gradients at different depths in oceanic crust (ODP Site 735B, South-West Indian Ocean)

Pietranik

Storey

Koepke

et al. 2017

Contrib Mineral Petrol

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Site 735B gabbro. Zircons from oxide gabbro are scarce and variable in composition consistent with their crystallization from melts formed by both fractionation of mafic magmas and hydrous remelting of gabbro cumulate. On the other hand, zircon from plagiogranite is abundant and each sample is characterized by compositional trends consistent with crystallization of zircon in an evolving melt. However, the trends are different between the plagiogranite at 500 m bsf and the deeper sections, which are interpreted as the record of plagiogranite formation by two processes: remelting of gabbro cumulate at 500 m bsf and fractionation at deeper sections. Zircon from both oxide gabbro and plagiogranite has δ 18 O from 3.5 to 6.0‰. Values of δ 18 O are best explained by redistribution of δ 18 O in a thermal gradient and not by remelting of hydrothermally altered crust. Tentatively, it is suggested that fractionation could be an older episode contemporaneous with gabbro crystallization and remelting could be a younger one, triggered by deformation and uplift of the crustal pile.

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Section: Zircon: Structure Chemical and Isotope Compositionmentioning

confidence: 99%

Section: Zircon: Structure Chemical and Isotope Compositionmentioning

confidence: 99%

Section: Zircon: Structure Chemical and Isotope Compositionmentioning

confidence: 99%

Section: Zircon: Comparison With Other Datasetsmentioning

confidence: 99%

See 2 more Smart Citations

Zircon record of fractionation, hydrous partial melting and thermal gradients at different depths in oceanic crust (ODP Site 735B, South-West Indian Ocean)

Pietranik

Storey

Koepke

et al. 2017

Contrib Mineral Petrol

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“…Analyses with low La concentrations (b0.1 ppm; Appendix E) and low La N /Yb N ratios (b0.003; Appendix D), all of which are indicative of significant heavy REE (HREE) enrichments (Fig. 3), are characteristic of unaltered magmatic zircons (Hoskin, 2005;Grimes et al, 2009;Bouvier et al, 2012).…”

Section: Zircon Oxygen Isotopesmentioning

confidence: 99%

Oxygen isotope and trace element geochemistry of zircons from porphyry copper system: Implications for Late Triassic metallogenesis within the Yidun Terrane, southeastern Tibetan Plateau

Kong

Chen

2016

Chemical Geology

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U‐Pb dating of interspersed gabbroic magmatism and hydrothermal metamorphism during lower crustal accretion, Vema lithospheric section, Mid‐Atlantic Ridge

et al. 2015

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New U/Pb analyses of zircon and xenotime constrain the timing of magmatism, magmatic assimilation, and hydrothermal metamorphism during formation of the lower crust at the Mid-Atlantic Ridge. The studied sample is an altered gabbro from the Vema lithospheric section (11°N). Primary gabbroic minerals have been almost completely replaced by multiple hydrothermal overprints: cummingtonitic amphibole and albite formed during high-temperature hydration reactions and are overgrown first by kerolite and then prehnite and chlorite. In a previous study, clear inclusion-free zircons from the sample yielded Th-corrected 206 Pb/ 238 U dates of 13.528 ± 0.101 to 13.353 ± 0.057 Ma. Ti concentrations, reported here, zoning patterns and calculated Th/U of the dated grains are consistent with these zircons having grown during igneous crystallization. To determine the timing of hydrothermal metamorphism, we dated a second population of zircons, with ubiquitous <1-20 μm chlorite inclusions, and xenotimes that postdate formation of metamorphic albite. The textures and inclusions of the inclusion-rich zircons suggest that they formed by coupled dissolution-reprecipitation of metastable igneous zircon during or following hydrothermal metamorphism. Th-corrected 206 Pb/ 238 U dates for the inclusion-rich zircons range from 13.598 ± 0.012 to 13.503 ± 0.018 Ma and predate crystallization of all but one of the inclusion-free zircons, suggesting that the inclusion-rich zircons were assimilated from older hydrothermally altered wall rocks. The xenotime dates are sensitive to the Th correction applied, but even using a maximum correction, 206 Pb/ 238 U dates range from 13.341 ± 0.162 to 12.993 ± 0.055 Ma and postdate crystallization of both the inclusion-rich zircons and inclusion-free igneous zircons, reflecting a second hydrothermal event. The data provide evidence for alternating magmatism and hydrothermal metamorphism at or near the ridge axis during accretion of the lower crust at a ridge-transform intersection and suggest that hydrothermally altered crust was assimilated into younger gabbroic magmas. The results of this study show that high-precision U-Pb dating is a powerful method for studying the timing of magmatic and hydrothermal processes at mid-ocean ridges.

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On the occurrence, trace element geochemistry, and crystallization history of zircon from in situ ocean lithosphere

Cited by 258 publications

References 83 publications

Zircon record of fractionation, hydrous partial melting and thermal gradients at different depths in oceanic crust (ODP Site 735B, South-West Indian Ocean)

Zircon record of fractionation, hydrous partial melting and thermal gradients at different depths in oceanic crust (ODP Site 735B, South-West Indian Ocean)

Oxygen isotope and trace element geochemistry of zircons from porphyry copper system: Implications for Late Triassic metallogenesis within the Yidun Terrane, southeastern Tibetan Plateau

U‐Pb dating of interspersed gabbroic magmatism and hydrothermal metamorphism during lower crustal accretion, Vema lithospheric section, Mid‐Atlantic Ridge

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