Contrasting latest Permian intracontinental gabbro and Late Triassic arc gabbro–diorite in the Gangdese constrain the subduction initiation of the Neo-Tethys

Li, Qiu-Huan; Zhang, Kai-Jun; Yan, Lilong; Jin, Xin

doi:10.1080/00206814.2020.1836682

Cited by 7 publications

(3 citation statements)

References 73 publications

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“…As discussed above, the geochemical characteristics of the middle-late Triassic basic rocks in Halaqi provide a certain inheritance to the Tarim Permian LIP. In addition, previous studies have also found that the heat associated with mantle plumes tends to be contained in the mantle near the plume for a considerable time [60,61]. Therefore, we consider that the Triassic mafic magmatism in northwest Tarim could be the product of the continuous thermal pulse of the Tarim mantle plume and be a part of the Tarim LIP.…”

Section: Tectonic Significancementioning

confidence: 82%

Triassic Thermal Pulse of TARIM Mantle Plume: Evidence from Geochronology, Geochemistry, and Nd Isotopes of the Mafic Dikes from the Halaqi Area, Xinjiang, China

Sun,

Liang,

Liu

et al. 2024

Minerals

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Owing to the paucity of research on synchronous mafic rocks in the Tarim Basin, the late Paleozoic–early Mesozoic tectonic development of this region is not well defined. The Halaqi region is situated on Tarim’s northwest edge, and numerous mafic dikes can be found cross-cutting the Permian strata. The whole-rock geochemistry, zircon U–Pb age, and Sr–Nd isotopic signature of these mafic rocks have never been reported before, and this contribution can offer geochronological and petrogenetic investigations that provide fresh insight into the geodynamic development of the area. Major oxide contents in the Halaqi mafic rocks vary, including SiO2 (45.74–50.31 wt.%), Al2O3 (13.28–14.8 wt.%), FeOT (16.48–19.19 wt.%), MgO (7.58–10.32 wt.%), CaO (7.19–12.39 wt.%), Na2O (2.97–4.50 wt.%), K2O (0.24–0.63 wt.%), TiO2 (1.11–1.29 wt.%), MnO (0.14–0.16 wt.%), and P2O5 (0.13–0.17 wt.%). The mafic rocks are enriched in high-field-strength elements (e.g., Zr and Hf) and large-ion lithophile elements (e.g., Sr, Th, and U) but depleted in Nb, Ta, and P. The total REEs in the rocks are lower (ΣREE = 72.80–86.85 ppm), and HREEs are somewhat depleted in comparison to LREEs, with positive Eu anomalies (Eu/Eu* = 1.05–1.17) but weak negative Ce anomalies (Ce/Ce* = 0.91–0.93). Zircon U–Pb ages of 201–247 Ma were obtained from a total of 18 magmatic zircon grains found in the mafic rocks that were studied. These results point to a middle-to-late Triassic emplacement. The mafic dikes exhibit somewhat enriched Nd isotopic compositions (εNd(t) = –1.6~–0.2) and an older Nd model age (TDM = 1.24–1.37 Ga). The Halaqi middle–late Triassic mafic dikes are thought to have originated from the same tectonic background as the Permian Tarim Large Igneous Province, along with similar geochemical and isotopic compositions. This suggests that they are all products of the interaction between asthenospheric and lithospheric mantles in an intraplate extensional environment. Research indicates that the Triassic mafic magmatism in northwest Tarim could be the product of the continuous thermal pulse of the Tarim mantle plume and be a part of the Tarim LIP.

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Section: Tectonic Significancementioning

confidence: 82%

Triassic Thermal Pulse of TARIM Mantle Plume: Evidence from Geochronology, Geochemistry, and Nd Isotopes of the Mafic Dikes from the Halaqi Area, Xinjiang, China

Sun,

Liang,

Liu

et al. 2024

Minerals

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“…The results of the zircon saturation thermometer ( t [Ti], Table S2) suggest that the parental magmas of the Luerma complex crystallized in a high‐temperature ( t [Ti] = 905–1076°C) and H 2 0‐rich environment. Li, Zhang, Yan, and Jin (2020) obtained augite inclusions that yielded pressure and temperature conditions of 1460 MPa and 1280°C, respectively, supporting that the late Permian magma could have been derived from lithospheric mantle melting.…”

Section: Discussionmentioning

confidence: 94%

Petrogenesis and tectonic environment of the Middle Permian Luerma igneous complex in the southern Lhasa subterrane, Tibet: Evidence from geochemistry; Rb–Sr, Sm–Nd, and Lu–Hf isotopes; and zircon U–Pb geochronology

Liu

et al. 2023

Geological Journal

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Due to the lack of corresponding magmatic records, the timing of the opening of the Yarlung–Tsangpo Neo‐Tethyan Ocean remains controversial. The Middle Permian Luerma igneous complex, which is situated in the western Gangdese magmatic belt of the southern Lhasa subterrane, western Tibet, can be divided into four or more rock types, including foid gabbro, amphibole gabbro, monzogabbro, and pyroxene‐bearing monzodiorite. Through zircon U–Pb dating using laser ablation–inductively coupled plasma–mass spectrometry, the age of the Luerma igneous complex is determined to be ~261 Ma. The complex is rich in titanium, iron, magnesium, and total alkalis, with medium to high levels of calcium, potassium and aluminium, as well as low levels of silicon. Therefore, it is classified as a shoshonite–latite rock series. The complex is relatively enriched in light rare earth elements and high‐field‐strength elements, without obvious Eu and Ce anomalies. These rocks exhibit relatively low (87Sr/86Sr)i values, high εNd(t) values, and high εHf(t) values. The geochemical and isotopic characteristics indicate that the magmas are derived from partial melting of the upper mantle in an intraplate tectonic environment. The new data presented here provide supplementary evidence for the initial rifting of the Lhasa terrane from the northern margin of Gondwana during the Middle Permian. These data also confirm that the opening of the Yarlung–Tsangpo Neo‐Tethyan Ocean occurred in the Middle Permian.

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“…The helium isotopic compositions generally exhibit distinct variations between the two region, with the 3 He/ 4 He ratios in the southern region samples being lower than those in the northern region samples, possibly because of subducted plate characteristics (Figure S4 in Supporting Information S1). Helium in the southern region is primarily of crustal radiogenic origin (more than 95%), with slight mantle influence as U (∼3 ppm) and Th (∼20 ppm) within crustal granitic rocks (Li et al., 2021), while the northern region displays more pronounced mantle‐derived helium (with some samples exhibiting nearly 20%), albeit with still major contributions from crustal radiogenic sources (Figure S4 in Supporting Information S1).…”

Section: Discussionmentioning

confidence: 99%

Organic and Inorganic Carbon Sinks Reduce Long‐Term Deep Carbon Emissions in the Continental Collision Margin of the Southern Tibetan Plateau: Implications for Cenozoic Climate Cooling

Wang,

Quan,

Tang

et al. 2024

JGR Solid Earth

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This paper aims to update our understanding of the carbon cycle in the Himalayas, the most intense collisional orogeny globally, by providing new insight into its impact on Cenozoic climate cooling through the use of isotopic variations in both organic and inorganic carbon and an isotopic mass balance model. Our results from 20 selected hot springs show that the relative contributions of dissolved carbon from the mantle, metamorphic decarbonization, aqueous dissolution, and soil organic matter are approximately 2%, 82%, 6%, and 10%, respectively. Approximately 87% ± 5% of CO2 generated in the deep crust precipitates as calcite, while approximately 5.5% ± 1% of this carbon is converted to biomass through microbial chemosynthesis at depths less than 2 km. Our random forests approach yielded a metamorphic carbon flux from the entire Himalayan orogenic belt of approximately 2.7 ∼ 4.5 × 1012 mol/yr. The minor CO2 released into the atmosphere (2.5 ∼ 4.2 × 1011 mol/yr) is comparable to the carbon consumption driven by Himalayan weathering. This paper provides new insights into deep carbon cycling, notably that approximately 93% of deeply sourced carbon is trapped in the shallow crust, rendering orogenic processes carbon neutral and possibly acting as one of the major triggers of long‐term climate cooling in the Cenozoic.

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Contrasting latest Permian intracontinental gabbro and Late Triassic arc gabbro–diorite in the Gangdese constrain the subduction initiation of the Neo-Tethys

Cited by 7 publications

References 73 publications

Triassic Thermal Pulse of TARIM Mantle Plume: Evidence from Geochronology, Geochemistry, and Nd Isotopes of the Mafic Dikes from the Halaqi Area, Xinjiang, China

Triassic Thermal Pulse of TARIM Mantle Plume: Evidence from Geochronology, Geochemistry, and Nd Isotopes of the Mafic Dikes from the Halaqi Area, Xinjiang, China

Petrogenesis and tectonic environment of the Middle Permian Luerma igneous complex in the southern Lhasa subterrane, Tibet: Evidence from geochemistry; Rb–Sr, Sm–Nd, and Lu–Hf isotopes; and zircon U–Pb geochronology

Organic and Inorganic Carbon Sinks Reduce Long‐Term Deep Carbon Emissions in the Continental Collision Margin of the Southern Tibetan Plateau: Implications for Cenozoic Climate Cooling

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