Late Paleoproterozoic ultrahigh-temperature mafic granulite from the eastern Alxa Block, North China Craton

Wang, Yue; Ge, Rongfeng; Si, Yang

doi:10.1016/j.precamres.2023.107172

Cited by 5 publications

(12 citation statements)

References 131 publications

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“…1.95-1.83 Ga, which recorded a clockwise P-T path with peak metamorphic conditions of ~890-940 • C at ~7.5-9.8 kbar [34]. Wang et al (2023) [35] obtained a clockwise P-T path with the peak metamorphic condition of 948-1048 • C/11-14 kbar, and metamorphic ages of ca. 1.96-1.86 Ga for mafic granulites.…”

Section: The Eastern Alxa Blockmentioning

confidence: 98%

“…The Diebusige Complex mainly consists of felsic gneisses, amphibolite, and minor metasedimentary rocks (e.g., banded iron formations and pelitic gneisses) [29,[32][33][34][35][36]42]. SHRIMP and SIMS zircon U-Pb dating yielded protolith crystallization ages of ca.…”

Section: The Eastern Alxa Blockmentioning

confidence: 99%

“…1.90-1.80 Ga metamorphism [36,42]. These late Paleoproterozoic metamorphic ages in the Diebusige and Bayanwulashan Complexes indicate that the Alxa Block may be the westward extension of the KB [27,30,[33][34][35].…”

Section: The Eastern Alxa Blockmentioning

confidence: 99%

“…1.96-1.83 Ga metamorphism, ca. 2.3-2.0 Ga magmatism and small-scale Neoarchean magmatism in this block [27][28][29][30][31][32][33][34][35]. Therefore, the relationship between the Alxa Block and the NCC has become the focus of controversy, and research on metamorphism can provide important insights for solving this dispute.…”

Section: Introductionmentioning

confidence: 99%

“…1.93-1.81 Ga [36,37], which are comparable to published metamorphic ages of ca. 1.96-1.83 Ga for high-to ultrahigh-temperature (HT-HUT) metamorphic rocks in the Diebusige Complex [33][34][35]. Due to the lack of detailed metamorphic PT condition calculations for these amphibolites, their relationship with HT-UHT metamorphic rocks, and the implications for tectonic evolution of the Alxa Block are unclear until now.…”

Section: Introductionmentioning

confidence: 99%

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Metamorphic Ages and PT Conditions of Amphibolites in the Diebusige and Bayanwulashan Complexes of the Alxa Block, North China Craton

Zhou,

Gou,

et al. 2023

Minerals

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The metamorphism and geological significance of amphibolites in the Diebusige and Bayanwulashan Complexes of the eastern Alxa Block, North China Craton, were poorly understood until now. This study presents the results of petrology, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) zircon U–Pb analysis, phase equilibrium modeling and geothermobarometry for these rocks. The peak mineral assemblage of clinopyroxene + hornblende + plagioclase + K-feldspar + ilmenite + quartz + melt is inferred for amphibolite sample ALS2164 in the Diebusige Complex. Correspondingly, the peak mineral assemblage of clinopyroxene + hornblende + plagioclase ± K-feldspar + ilmenite + quartz + melt is identified for amphibolite sample ALS2191 in the Bayanwulshan Complex. Phase equilibrium modelling constrained the peak metamorphic condition of amphibolite sample ALS2164 in the Diebusige Complex to be 825–910 °C/7.2–10.8 kbar, which is similar to that (800–870 °C/7.0–10.7 kbar) of amphibolite sample ALS2191 in the Bayanwulashan Complex. Hbl–pl–qz thermobarometry yielded the metamorphic PT conditions of 732–810 °C/3.0–6.7 kbar for these amphibolites, which are consistent with the average temperatures of 763 °C, 768 °C and 780 °C calculated by Ti-zircon thermometry. As a result, phase equilibrium modelling yielded wide PT condition ranges of 800–910 °C/7.0–10.8 kbar, the lower limit of which is consistent with the upper limit of estimates by the hbl–pl–qz thermobarometer. In addition, LA-ICP-MS U–Pb analysis on metamorphic zircons yielded weighted mean 207Pb/206Pb ages of 1901 ± 22–1817 ± 21 Ma, which represent the timing of amphibolite-facies metamorphism. As a whole, the PT estimates display a high geothermal gradient, which is consistent with coeval ultrahigh-temperature metamorphism and associated mantle-derived mafic-ultramafic rocks in the Diebusige Complex. Combing this information with the previously published data from the Diebusige Complex, an extensional setting after continental collision is inferred for the eastern Alxa Block during the late Paleoproterozoic. The HREE enrichment patterns of metamorphic zircons from the amphibolites in this study are in agreement with that these amphibolites formed at relatively shallower crust than the garnet-bearing mafic granulites in the Diebusige Complex.

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Section: The Eastern Alxa Blockmentioning

confidence: 98%