Emplacement ages of diamondiferous kimberlites in the Wafangdian District, North China Craton: New evidence from LA-ICP-MS U-Pb geochronology of andradite-rich garnet

Li, Dongsheng; Wu, Zhongwei; Sun, Xiaoming; Shi, Song; Fu, Yu; Li, Dengfeng; Chen, Hongjun; Yang, Ling; Hong, Lu-Bing

doi:10.1016/j.gr.2022.05.016

Cited by 5 publications

(5 citation statements)

References 136 publications

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“…Therefore, the determined garnet U–Pb age from mantle will most commonly relate to magmatic emplacement rather than garnet formation (cf. Li et al 2022) or subsequent metasomatic alteration.…”

Section: Introductionmentioning

confidence: 99%

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Uranium–lead geochronology applied to pyrope garnet with very low concentrations of uranium

O’Sullivan

Hoare²,

Mark

et al. 2023

Geol. Mag.

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We present U–Pb dates from peridotitic pyrope-rich garnet from four mantle xenoliths entrained in a kimberlite from Bultfontein, South Africa. Garnet dates magmatic emplacement due to the high mantle residence temperatures of the source material prior to eruption, which were most likely above the closure temperature for the pyrope U–Pb system. We determine a U–Pb date of 84.0 ± 8.1 Ma for the emplacement of the Bultfontein kimberlite from garnet in our four xenolith samples. The date reproduces previous dates obtained from other mineral-isotope systems (chiefly Rb–Sr in phlogopite). Garnet can be dated despite extremely low concentrations of U (median ∼0.05 μg/g), because concentrations of common Pb are often low or non-detectable. This means that sub-concordant garnets can be dated with moderate precision using very large laser-ablation spots (130 μm) measured by quadrupole inductively coupled plasma – mass spectrometry (LA-Q-ICP-MS). Our strategy demonstrates successful U–Pb dating of a U-poor mineral due to high initial ratios of U to common Pb in some grains, and the wide spread of isotopic compositions of grains on a concordia diagram. In addition, the analytical protocol is not complex and uses widely available analytical methods and strategies. This new methodology has some advantages and disadvantages for dating kimberlite emplacement versus established methods (U-based decay systems in perovskite and zircon, or Rb- or K-based systems in phlogopite). However, this method has unique promise for its potential application to detrital diamond prospecting and, more speculatively, to the dating of pyrope inclusions in diamond.

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Section: Introductionmentioning

confidence: 99%

“…U–Pb dating has also been applied to magmatic andraditic garnet from within the kimberlite groundmass (Li et al 2022). However, such garnet is rare in kimberlite, more commonly occurring in ultramafic lamprophyres and orangeites (Mitchell, 1995).…”

Section: Introductionmentioning

confidence: 99%

Uranium–lead geochronology applied to pyrope garnet with very low concentrations of uranium

O’Sullivan

Hoare²,

Mark

et al. 2023

Geol. Mag.

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“…Wafangdian and Mengyin are diamond-producing areas located in the eastern part of the NCC. The timing of diamondiferous kimberlites and the related magmatism in the NCC has been extensively investigated through the determination of perovskite U-Pb ages (Mengyin = 480.6 ± 2.9 Ma and 470 ± 4 Ma, respectively) [32,33], in situ calcite U-Pb ages (Mengyin = 383 ± 18 Ma) [34], baddeleyite Pb-Pb ages (Mengyin = 480.4 ± 3.9 Ma, Fuxian = 479.6 ± 3.9 Ma) [32], andradite phenocryst U-Pb ages (Wafangdian = 459.3 ± 3.4 Ma) [35], the Ar-Ar geochronology of the phlogopite megacryst ages (465 ± 2 Ma), and phlogopite Rb-Sr isochron ages (452-465 Ma) [36]. Using a suite of kimberlite samples collected from the central Shandong and Wafangdian regions, these data show that the kimberlite magmatic activity in the eastern part of the NCC is concentrated in the middle to late Ordovician period.…”

Section: Geologic Settingmentioning

confidence: 99%

“…Our results are roughly similar to the results of previous studies, which fully demonstrates the credibility of our results. Based on LA-ICP-MS U-Pb dating of the apatite in the kimberlite in Wafangdian, it can be concluded that the kimberlite magmatic activity in the eastern part of the NCC occurred mainly in the Middle to Late Ordovician [32,34,35]. The age obtained via in situ U-Pb geochronology of the apatite in this study is slightly younger than that obtained in previous studies via Rb-Sr and Ar-Ar dating of phlogopite, which is consistent with the conclusion that the crystallization of the phlogopite occurred slightly earlier than that of the apatite.…”

Section: Crystallization Age Of the Wafangdian Kimberlitementioning

confidence: 99%

Geochemistry, Sr-Nd Isotope Compositions, and U-Pb Chronology of Apatite from Kimberlite in Wafangdian, North China Craton: Constraints on the Late Magmatic Processes

Ma,

Wang,

et al. 2024

Minerals

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Diamondiferous kimberlites occur in the Wafangdian area in the eastern part of the North China Craton (NCC). In order to better constrain their magmatic source and emplacement time, we have investigated apatite from two kimberlites, i.e., the #110 dike kimberlite and the #50 root-zone kimberlite by measuring in situ their U–Pb and Sr–Nd isotopic compositions. The crystallization ages of the #110 and #50 apatites are 460.9 ± 16.8 Ma and 455.4 ± 19.3 Ma, respectively. For the #50 apatite, 87Sr/86Sr = 0.70453–0.70613 and εNd(t) = −2.74 to −4.52. For the #110 apatite, 87Sr/86Sr = 0.70394–0.70478 and εNd(t) = −3.46 to −5.65. Based on the similar distribution patterns of the rare earth elements (REEs) and the similar Sr-Nd isotope compositions of the apatite, it is believed that the #110 and #50 kimberlites have the same source region and the kimberlite magmas in Wafangdian were derived from an enriched mantle source (EMI). The primary magmatic composition has little effect on the emplacement pattern. It is more likely that the geological environment played an important role in controlling the retention and removal of volatile components (H2O and CO2). This led to the different evolutionary paths of the kimberlite magma in the later period, resulting in differences in the major element compositions of the apatite. High Sr concentrations may be associated with hydrothermal (H2O-rich fluid) overprinting events in the later magmatic period; the higher light rare earth element (LREE) concentration of the #50 apatite reflects the involvement of the REE3+ + SiO44− ⇔ Ca2+ + PO43− replacement mechanism. Two emplacement patterns of the #110 dike kimberlite (#110 apatite, low Sr, and high Si) and the #50 root-zone (#50 apatite, high Sr, and low Si) kimberlites were identified via major element analysis of the #110 apatite and #50 apatite.

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“…Worldwide, over the last few decades, much information about the magma evolution and lithology determination of kimberlites has been gleaned from the zonal structure of olivine elsewhere in the past [2,[29][30][31][32][33][34][35][36]. Currently, global research on minerals in kimberlite primarily focuses on olivine, garnet, perovskite, and spinel [37][38][39][40][41][42][43][44][45][46]. The olivine found in southern Liaoning's kimberlite typically exhibits pronounced serpentinization, posing challenges for comprehensive investigation.…”

Section: Introductionmentioning

confidence: 99%

Revealing the Magmatic Impulse Emplacement and Evolution Path of Kimberlite in Southern Liaoning through Mineralogical Characteristics of the Phlogopite Zone

Ma,

Wang,

2024

Applied Sciences

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Phlogopite is a crucial indicator for effectively constraining the magmatic evolution and emplacement mechanism of kimberlite. In this study, samples were collected from the No. 110 kimberlite pipe within diamond belt I and the No. 50 kimberlite pipe within diamond belt II in the southern Liaoning diamond mining area in the eastern North China Craton (NCC). Zonation is highly developed in the phlogopite; the major and trace element compositions of the phlogopite zonation in the samples were analyzed. In this study, phlogopite from the No. 50 pipe kimberlite (#50 phlogopite) zonation is divided into the following components: (1) The cores, low Ti-Cr xenocryst, average Mg# = 90.6, has a resorption structure, the presence of serpentine and talc minerals in low Ti-Cr cores (xenocrysts) can be used as evidence for hydrothermal metasomatism; (2) cores/inner rims (between core and outer rim), high Ti-Cr, it is thought to be related to the assimilation of mantle materials by deep kimberlite magma, average Mg# = 88.2; (3) outer rims, low-Cr/Cr-poor, average Mg# = 82.4, Fe, Al and Ba contents increased, and there was a trend of evolution to biotite composition believed to be related to the metasomatic metamorphism of melt and wall rock during the late magmatic evolution or ascent; (4) rinds, it is characterized by re-enrichment of Mg, rind I (low-Ti-Cr, average Mg# = 88.4), rind II (high-Ti-Cr, Mg# = 88.6), rind II may be formed earlier than rind I. Rind is very rare and has been reported for the first time in southern Liaoning kimberlite. This study was only accidentally found in the outermost part of #50 phlogopite, the Mg-rich feature represents an environment in which oxygen fugacity has increased. The phlogopite in samples from pipe No. 110 (#110 phlogopite) exhibits relatively homogeneous characteristics across different zones and is more enriched in Al and Ba, which is likely the result of mantle metasomatism. Due to its euhedral characteristics and limited composition variation, it is considered that #110 phlogopite is more likely to be derived from direct crystallization from magma than from xenocrysts. In addition, based on the simultaneous enrichment of Al and Fe in phlogopite from the core to the outer rim, pipe No. 50 was determined to be a micaceous kimberlite, while pipe No. 110 more closely resembles group I kimberlites. This paper proposes that successive pulses of kimberlite magma emplacement gradually metasomatized the conduit, and subsequent kimberlite magma ascended along the metasomatized conduit, thereby minimizing the interaction between the later magma and the surrounding mantle lithosphere.

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Emplacement ages of diamondiferous kimberlites in the Wafangdian District, North China Craton: New evidence from LA-ICP-MS U-Pb geochronology of andradite-rich garnet

Cited by 5 publications

References 136 publications

Uranium–lead geochronology applied to pyrope garnet with very low concentrations of uranium

Uranium–lead geochronology applied to pyrope garnet with very low concentrations of uranium

Geochemistry, Sr-Nd Isotope Compositions, and U-Pb Chronology of Apatite from Kimberlite in Wafangdian, North China Craton: Constraints on the Late Magmatic Processes

Revealing the Magmatic Impulse Emplacement and Evolution Path of Kimberlite in Southern Liaoning through Mineralogical Characteristics of the Phlogopite Zone

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