Double-layer structure of the crust beneath the Zhongdian arc, SW China: U–Pb geochronology and Hf isotope evidence

Cao, Kang; Xu, Ji‐Feng; Chen, Jianlin; Huang, Xiaoxiao; Ren, Jiangbo; Zhao, Xin; Liu, Zhenxing

doi:10.1016/j.jseaes.2015.10.024

Cited by 45 publications

(36 citation statements)

References 53 publications

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“…(d) (Na 2 O + K 2 O)/CaO versus (Zr + Nb + Ce + Y) diagram (Whalen et al, ). The data set for the SYT Late Triassic granitoid (220–206 Ma) was originated from Wang et al () and Cao et al (). Note .…”

Section: Analytical Methods and Resultsmentioning

confidence: 99%

Geochronology, mineralogy, and geochemistry of the Late Triassic Xiuwacu biotite granite in the southern Yidun Terrane, southwest China: Insights into the petrogenesis and magmatic fertility

et al. 2019

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The southern Yidun Terrane formed in response to the westward subduction of the Garzê-Litang oceanic lithosphere. The Xiuwacu pluton, consisting of the Late Triassic biotite granite and Late Cretaceous monzogranite porphyry, is located in the northern portion of the southern Yidun Terrane. It hosts the Late Cretaceous quartz-vein-type Mo-W deposit genetically related to the intraplate monzogranite porphyry. However, the petrogenesis and magmatic fertility of the biotite granite remain unclear. Sixteen zircons from the biotite granite yield a weighted mean 206 Pb/ 238 U age of 217 ± 1.2 Ma, indicating that the biotite granite emplaced synchronously with the arc-related andesites and porphyries in the southern Yidun Terrane. Unlike these slab melt-derived adakitic rocks, the Xiuwacu biotite granites show typical I-type granite affinities, with relatively high SiO 2 contents, low Sr/Y ratios, and high Y contents. These granites display depleted zircon Hf isotopic signatures (ƐHf(t) = 0.6-3.8) but enriched whole-rock Sr-Nd and zircon O isotopic signatures, suggesting that the mixing between juvenile materials and external enriched melts might have contributed to the generation of biotite granite. Moreover, they show relatively high Al 2 O 3 / (FeO T + MgO + TiO 2 ), Th/Yb, and Th/Nb ratios, which are collectively indicative of the input of sediment melts extracted from subducting slab into the melt source of biotite granite. The high MgO, TiO 2 , F, and Cl contents of biotite and the excess Al of plagioclase suggest that the Xiuwacu biotite granites formed under high oxygen fugacities, magmatic water contents, and volatiles components and they might have Cu prospecting potentials.

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Section: Analytical Methods and Resultsmentioning

confidence: 99%

Geochronology, mineralogy, and geochemistry of the Late Triassic Xiuwacu biotite granite in the southern Yidun Terrane, southwest China: Insights into the petrogenesis and magmatic fertility

et al. 2019

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“…This is also supported by zircon ε Hf ( t ) values of −9.9 to +3.4 with two‐stage Hf model ages (T DM2 ) of 1.88 to 1.04 Ga (Figures and ), indicating that they were probably derived from partial melting of a Late Paleoproterozoic to Early Mesoproterozoic lower crust with a variably minor addition (<20%) of depleted mantle‐derived magma (He et al, ). But, some porphyries in the Zhongdian area also show variable ε Hf ( t ) values (−9.9–+6.3) and young T DM2 model ages (1.88–0.85 Ga), indicating that they were most likely derived from a juvenile mafic lower crust with minor old crustal material (Cao et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, both Group 1 and Group 2 show variable Sr i values of 0.7046 to 0.7102, predominately negative ε Nd ( t ) values of −7.8 to −1.4, and T DM model ages from 1.85 to 0.98 Ga (e.g., Wang, Zhou, et al, ; He et al, ; Chen et al, ; Wu, Xiao, et al, ; Figure ). They also have variable zircon ε Hf ( t ) values of −9.9 to +6.3 with two‐stage Hf model ages (T DM2 ) of 1.88 to 0.85 Ga (He et al, ; Cao et al, ; Wu, Xiao, et al, ; Figure. ).…”

Section: The Temporal‐spatial Distribution and Characteristics Of Earmentioning

confidence: 99%

Early Mesozoic Magmatism Within the Tibetan Plateau: Implications for the Paleo‐Tethyan Tectonic Evolution and Continental Amalgamation

Chung

Hou

et al. 2019

Tectonics

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Numerous early Mesozoic magmatic rocks within the Tibetan Plateau ultimately have a geodynamic controll caused by the Paleo-Tethyan tectonic evolution and the assembly of Pangea. Based on their temporal variation and the timing of closure (235 ± 10 Ma) of the Paleo-Tethys Ocean, they can be broadly divided into two groups by zircon U-Pb geochronology: an Early to Middle Triassic (252-235 Ma) group and a Late Triassic to Early Jurassic (ca. 235-190 Ma) group. Early magmatic rocks are mainly found in the middle northern Tibetan Plateau, whereas late magmatic rocks are more widespread in the whole Tibetan Plateau. Nd and Hf isotope mapping suggests that the eastern segment of the Qiangtang is underlain by old (late Archean to early Paleoproterozoic) basement, while Southern Lhasa is underlain by juvenile lower crust, which yields Neoproterozoic to early Paleozoic model ages. Early Mesozoic tectonomagmatism was likely caused by episodic southward opening of multi-Tethys oceans, punctuated by episodes of subduction and collision. The Middle to Late Permian tectonomagmatic history of Paleo-Tethys was dominated by continental arc-related systems. During the Early to Middle Triassic, the tectonomagmatic history was associated with the ongoing closure of the Paleo-Tethys Ocean and a tectonic transition from subduction to collision. Late Triassic tectonomagmatism formed in a post-collisional setting following the closure of the Paleo-Tethys Ocean and the ultimate assembly of Pangea. Early Mesozoic magmatism within the Tibetan Plateau thus provides crucial information on the history of oceanic-continental evolution and helps constrain the tectonic transition from subduction/accretion through to collision/postcollision for East Paleo-Tethys.Plain Language Summary The Tibetan Plateau was amalgamated by the successive northward drift of continental crustal fragments away from Gondwanaland and their subsequent collision with the southern margin of Asia during the Mesozoic to Cenozoic. However, our knowledge of the tectonic history of the Paleo-Tethys Ocean and continental amalgamation in the Tibetan Plateau prior to its demise during the early Mesozoic still remains poorly understood. Therefore, understanding the tectonomagmatic history and geodynamic evolution of the Paleo-Tethys Ocean and the ultimate assembly of Pangea in the early Mesozoic, and the subsequent opening and subduction history of the Meso/Neo-Tethys Ocean, is key to deciphering the evolution of Eurasia and Tethys, particularly for understanding the paleogeography and accretion-collision history that preconditioned the Tibetan lithosphere for subsequent collisional/postcollisional events and surface uplift. In our interpretations, Early Mesozoic tectonomagmatism requires episodic southward opening of multi-Tethys oceans, punctuated by episodes of subduction and collision with two-stages of magmatic evolution and crustal growth.This review pulls together the available information on the early Mesozoic magmatism within the Tibetan Plateau in order to reconstruct t...

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“…The Late Triassic porphyries are characterized by high Sr/Y, which is considered to be closely related to the porphyry deposits (Wang et al 2011(Wang et al , 2017Cao et al 2016). Although high Sr/Y magma can be generated through the melting of oceanic crust (Defant & Drummond, 1990), partial melting of lower crust (Ma et al 2015) or partial melting of a peridotitic mantle that has been modified by slab melts (Martin et al 2005), the trace-element contents of magma can be easily changed by crustal contamination or magmatic processes (Richards, 2011), and thus cannot be used as an indicator of specific petrogenesis.…”

Section: Introductionmentioning

confidence: 99%

“…Although high Sr/Y magma can be generated through the melting of oceanic crust (Defant & Drummond, 1990), partial melting of lower crust (Ma et al 2015) or partial melting of a peridotitic mantle that has been modified by slab melts (Martin et al 2005), the trace-element contents of magma can be easily changed by crustal contamination or magmatic processes (Richards, 2011), and thus cannot be used as an indicator of specific petrogenesis. Previous studies have focused on utilizing the properties of high Sr/Y and La/Yb to constrain the petrogenesis and related mineralization of the porphyries in the ZA (Wang et al 2011(Wang et al , 2017Cao et al 2016) but have neglected the origin of the high Sr/Y and La/Yb.…”

Section: Introductionmentioning

confidence: 99%

Late Triassic porphyries in the Zhongdian arc, eastern Tibet: origin and implications for Cu mineralization

et al. 2019

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Whole-rock and Sr–Nd–Pb isotopic composition data, zircon Hf isotopic data and zircon U–Pb ages were obtained for the Late Triassic porphyries in the Zhongdian arc, eastern Tibet. These porphyries are intermediate and metaluminous and are enriched in large ion lithophile elements and depleted in high field strength elements. Moreover, they have weak negative Eu anomalies, high Sr and Ba contents, and high Sr/Y ratios. Different mineral geothermobarometers suggest that the porphyries in the Zhongdian arc crystallized at c. 640–829 °C and pressures of 2.1–2.8 kbar at depths shallower than 8 km. The porphyries have a calculated water content of 4.47–4.94 wt % and a relatively high magmatic oxygen fugacity. These porphyries were emplaced mainly at 230–203 Ma with a peak at 218–215 Ma. The Sr–Nd–Pb–Hf isotope data suggest that the porphyries in the Zhongdian arc were derived from a mixed melt of 50–65 % asthenospheric mantle and 35–50 % eclogite from the western Yangtze lower crust that experienced low-degree partial melting of 2–10 %. Subsequent fractional crystallization resulted in the decreasing trends of the major- and trace-element contents. The high Sr/Y and La/Yb values are the result of the low degree of partial melting of the western Yangtze lower crust rather than fractional crystallization, because no linear relationship was noted between Sr/Y or La/Yb and SiO2. The mixed melts from the lower crust and asthenospheric mantle provided a fertile magma source, and subsequent fractional crystallization under the favourable magmatic conditions of high water content and high oxidation state resulted in the formation of the porphyry Cu–Au deposits.

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Double-layer structure of the crust beneath the Zhongdian arc, SW China: U–Pb geochronology and Hf isotope evidence

Cited by 45 publications

References 53 publications

Geochronology, mineralogy, and geochemistry of the Late Triassic Xiuwacu biotite granite in the southern Yidun Terrane, southwest China: Insights into the petrogenesis and magmatic fertility

Geochronology, mineralogy, and geochemistry of the Late Triassic Xiuwacu biotite granite in the southern Yidun Terrane, southwest China: Insights into the petrogenesis and magmatic fertility

Early Mesozoic Magmatism Within the Tibetan Plateau: Implications for the Paleo‐Tethyan Tectonic Evolution and Continental Amalgamation

Late Triassic porphyries in the Zhongdian arc, eastern Tibet: origin and implications for Cu mineralization

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