What Hf isotopes in zircon tell us about crust–mantle evolution

Iizuka, Tsuyoshi; Yamaguchi, Takao; Itano, Keita; Hibiya, Yuki; Suzuki, Kuninori

doi:10.1016/j.lithos.2017.01.006

Cited by 89 publications

(32 citation statements)

References 332 publications

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“…The Hf isotopic data suggest that the rocks with negative ε Hf ( t ) values are derived from the partial melting of the lower ancient crust (Griffin, Belousova, Shee, Pearson, & O'Reilly, ; Iizuka, Yamaguchi, Itano, Hibiya, & Suzuki, ; Vervoort et al, ). As shown in Figure a,b, most samples of the ore‐forming porphyritic syenogranite are plotted beneath the evolution line of the depleted mantle and chondrite and between 2.1–1.7 Ga crustal evolution lines.…”

Section: Discussionmentioning

confidence: 99%

Geochemical and geological characteristics of the granitic batholith and Yuku concealed Mo–W deposit at the southern margin of the North China Craton

et al. 2018

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Integrated gravity and magnetic prospecting in the Luanchuan ore cluster by the Henan Institute of Geological Survey has led to the recent discovery of the Yuku concealed porphyry Mo-W deposit. This research focuses on the geological, geochemical, and chronological features of the Yuku deposit, and it discusses the genesis of the deposit and its associated concealed granitic batholith. Skarn and/or hornfels occur in the contact zone between the granitic batholith and the wall rocks. The Mo mineralization is mostly hosted in porphyritic granites, whereas the large Mo-W deposits of the area (e.g., the Nannihu-Sandaozhuang Mo-W deposit) are mostly hosted in the skarn and hornfels. The laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) zircon U-Pb dating constrained three episodes of magmatic emplacement: (a) the porphyritic biotite monzogranite at 153.1 ± 1.2 Ma, (b) the ore-causative porphyritic syenogranite at 147.1 ± 1.3 to 148.0 ± 1.6 Ma, and (c) the last porphyritic monzogranite at 130.0 ± 1.3 Ma. The granitic batholiths have high contents of SiO 2 , Al 2 O 3 , and K 2 O + Na 2 O, obvious fractionation between the light and heavy rare earth elements [(La/Yb) N = 17.3-37.3], a negative Eu anomaly (δEu = 0.62-0.84), enrichment in Rb, Th, U, and Sr, and depletion of P and Ti. These features indicate the fractionation of plagioclase, amphibole, garnet, and rutile from the primary magmas or as residues in the source. The ε Hf (t) isotopic values of the zircons are concentrated between −21 and −13, with corresponding two-stage model ages (t DM2 ) between 2.1 and 1.7 Ga. The above characteristics indicate that the granitic batholiths were derived from the partial melting of the thickened lower crust during the Mesozoic to Cenozoic. The ore-forming fluids emplaced in the contact zone between the batholith and the wall rocks resulted in the metasomatic alteration and the deposition of Mo-W mineralization.

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Section: Discussionmentioning

confidence: 99%

Geochemical and geological characteristics of the granitic batholith and Yuku concealed Mo–W deposit at the southern margin of the North China Craton

et al. 2018

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“…Positive O isotope excursions above the mantle baseline (∼5.5 per mil) reflect the recycling of silicate crust that has undergone lowtemperature aqueous alteration at Earth's surface (i.e., sediment), while negative Hf isotope excursions reflect the recycling of old, felsic crust that has undergone less 176 Hf ingrowth than the convecting mantle. Zircon Hf and O isotope averages vary throughout the supercontinent cycle as the proportion and preservation of arc, rift, and collisional magmatism varies (29)(30)(31); such normal variations are observed throughout the entirety of the preserved record, with roughly the expected periodicity (SI Appendix, Fig. S11).…”

Section: Methodsmentioning

confidence: 92%

“…2a), close to the isotopic composition of a reservoir with chondritic Lu/Hf. Variations in zircon εHf at the global scale have been traditionally attributed to the supercontinent cycle (29)(30)(31). Indeed, moderate fluctuations in this global mean zircon εHf occur throughout Earth history on plate tectonic timescales, with significant spectral power at Wilson Cycle periods of ∼500-700 Myr (SI Appendix, Fig.…”

Section: Zircon Hf and O Isotope Systematicsmentioning

confidence: 99%

Neoproterozoic glacial origin of the Great Unconformity

Keller¹,

Husson²,

Mitchell³

et al. 2019

Preprint

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The Great Unconformity, a profound gap in Earth's stratigraphic record often evident below the base of the Cambrian system, has remained among the most enigmatic field observations in Earth science for over a century. While long associated directly or indirectly with the occurrence of the earliest complex animal fossils, a conclusive explanation for the formation and global extent of the Great Unconformity has remained elusive. Here we show that the Great Unconformity is associated with a set of large global oxygen and hafnium isotope excursions in magmatic zircon that suggest a late Neoproterozoic crustal erosion and sediment subduction event of unprecedented scale. These excursions, the Great Unconformity, preservational irregularities in the terrestrial bolide impact record, and the first-order pattern of Phanerozoic sedimentation can together be explained by spatially heterogeneous Neoproterozoic glacial erosion totaling a global average of three to five vertical kilometers, along with the subsequent thermal and isostatic consequences of this erosion for global continental freeboard.

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“…Relatively high zircon εHf (>0) and 176 Hf/ 177 Hf (>0.2828) values generally imply that the depleted crustal‐derived materials were generated due to mantle fractionation, whereas low values would indicate the partial melting of enriched crust and contamination of the crustal‐derived materials (Gardiner, Kirkland, & Van Kranendonk, ; Iizuka, Yamaguchi, Itano, Hibiya, & Suzuki, ; F. Y. Wu, Li, Zheng, & Gao, ). The εHf (t) and T DM 2 of zircon grains from the Cuonadong granitoids range from −2 to +4 (mean = +1.1) and 1.4 to 1.6 Ga (mean = 1.4 Ga), respectively.…”

Section: Discussionmentioning

confidence: 99%

Cambrian magmatism in the Tethys Himalaya and implications for the evolution of the Proto‐Tethys along the northern Gondwana margin: A case study and overview

Zhang

Santosh

et al. 2018

Geological Journal

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The Cuonadong Dome in southern Tibet is a newly discovered gneiss dome in the Tethys Himalaya. Here, we investigate the Late Cambrian augen gneiss (orthogneiss) within the core of this dome to address the controversy surrounding early Palaeozoic tectonic evolution of the northern margin of eastern Gondwana. We report new zircon laser ablation multicollector inductively coupled plasma mass spectrometry (LA‐(MC‐)ICP‐MS) U‐Pb ages, Lu‐Hf isotopes, whole‐rock major and trace element geochemistry, and Sr‐Nd‐Pb data on representative samples from the granitic gneiss. The weighted mean of 116 analyses of zircon grains yields an age of 498.2 ± 1.5 Ma (mean square weighted deviation [MSWD] = 1.2). Forty‐one spots analyses on these grains show consistent εHf (t) values of −2 to +4 (average = +1.1), corresponding to Hf crustal model age (TDM2) of 1.3 to 1.6 Ga (average = 1.39 Ga). The orthogneiss (metagranite) is characterized by high Si and K contents, with low Al, Mg, and Ti, and A/CNK values ranging from 0.87 to 0.98 with an average of 0.92, indicating a metaluminous composition and I‐type granitoid affinity. The granitoid displays significant enrichment in light rare earth elements (LREEs) and relatively flat high rare earth element (HREE) patterns, with strong negative Eu anomalies (Eu/Eu* = 0.26–0.31). The primitive mantle‐normalized trace elements show a relative enrichment in large‐ion lithophile elements, such as Rb, and high‐field strength elements, such as Th, U, Zr, and Hf, with depletion in Ba, Nb, Ta, Sr, P, and Ti. The rocks show high initial 87Sr/86Sr ratios (0.7221–0.7248) and low εNd (t) values (−8.9 to −7.3) with Nd model ages (TDM) of 1.79–1.91 Ga. Their radiogenic Pb isotopic compositions show (206Pb/204Pb)t = 18.804–19.110, (207Pb/204Pb)t = 15.730–15.768, and (208Pb/204Pb)t = 38.409–39.054, indicating an ancient upper middle continental crustal origin. Our study shows that the protolith of the metagranite was most likely derived from the partial melting of upper continental crust with a minor contribution of depleted mantle materials. Through integration of the regional information on early Palaeozoic magmatism and metamorphic events, we contend that the protolith of the Cuonadong granitic gneiss formed in an accretionary setting associated with the early Palaeozoic Proto‐Tethys Oceanic plate subduction beneath the Gondwana continent.

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What Hf isotopes in zircon tell us about crust–mantle evolution

Cited by 89 publications

References 332 publications

Geochemical and geological characteristics of the granitic batholith and Yuku concealed Mo–W deposit at the southern margin of the North China Craton

Geochemical and geological characteristics of the granitic batholith and Yuku concealed Mo–W deposit at the southern margin of the North China Craton

Neoproterozoic glacial origin of the Great Unconformity

Cambrian magmatism in the Tethys Himalaya and implications for the evolution of the Proto‐Tethys along the northern Gondwana margin: A case study and overview

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