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The volcano‐sedimentary sequences from the Weixi belt provide significance for the Sanjiang Paleo‐Tethys evolution. This manuscript constrains the ages of volcano‐sedimentary sequences by LA‐ICPMS U–Pb, including bimodal volcanics (245.0–244.0 Ma) from Pantiange Formation, trachyandesite–basaltic andesite (234 ± 2.0 Ma) from Cuiyibi Formation, high silica subalkaline rhyolite (221 ± 1.4 Ma) from Waigucun Formation and Early Jurassic high silica subalkaline rhyolite (184 ± 2.2 Ma). The volcanics show various Hf isotopic composition, which includes Middle Triassic dacite (εHf[t] = −15.7 to −8.5, TDM2 = 2,006–1,613 Ma), Late Triassic rhyolite (εHf(t) = −9.8 to +1.9, TDM2 = 1,667–1,021 Ma), Late Triassic trachyandesite (εHf(t) = +2.6 to +5.7, TDM2 = 990–816 Ma) and Early Jurassic rhyolite (εHf(t) = −2.7 to +1.1, TDM2 = 1,250–1,145 Ma). The Middle–Late Triassic volcanics exhibit similar characteristics, the content of SiO2 exerts positive correlation with K2O and negative correlation with oxide of Ti, Fe, Al, Mg, Ca, Mn and P. The Hf isotopic and geochemical features indicate that the Middle Triassic basalt and rhyolite derived from mantle and crust by crystal fractionation, respectively. The absence of Lower Jurassic strata and existence of Triassic bimodal volcanic sequences suggest that the middle Sanjiang Tethys Orogen experienced collision during the Middle Triassic with local extension resulting from oblique convergence. Late Triassic–Early Jurassic rhyolite exhibit high SiO2 (77.12–77.81 wt%), K2O (4.35–6.10 wt%), Na2O (1.91–3.15 wt%) content, and a negative Eu anomaly. Together with the sedimentary sequence, the middle Sanjiang Tethys Orogen evolved into post‐collision phase during Late Triassic – Early Jurassic. [ABSTRACT FROM AUTHOR]

Potassic magmatic rocks provide significant insights in understanding of mantle composition, evolution, and interaction with crust. Potassic magmatism along the Jinshajiang–Ailaoshan Paleo‐Tethyan suture has drawn much attention. Whereas igneous intrusion in the Simao terrane, west to Jinshajiang–Ailaoshan potassic magmatic belt has rarely been investigated. Hence, we present zircon U–Pb ages and Lu–Hf isotope and whole‐rock geochemistry for the Lianhuashan pluton. Zircon U–Pb dating from monzonite and quartz monzonite porphyry yield ages of 33.6 ± 0.2 and 33.5 ± 0.3 Ma, respectively. Monzonites are characterized by high K2O (4.93–5.16%) and K2O/Na2O (1.46–1.71), high Y (22.90–23.80 ppm), and Yb (1.87–2.21 ppm), relatively enrichment of light rare earth element (LREE). Zircons from monzonites show εHf(t) values ranging from −1.1 to +0.6 and crustal model ages (TDMC) between 1.04 and 1.15 Ga. These geochemical features suggest that parent magmas of the rocks originated from a metasomatized lithospheric mantle. Quartz monzonite porphyries are characterized by high Sr (836.00–1,529.00 ppm), Sr/Y (70.85–99.93) and La/Yb (32.31–49.83), low Y (11.80–15.60 ppm), and Yb (0.95–1.30 ppm), enrichment in LREE and depletion in heavy rare earth elements (HREE). Quartz monzonite porphyries have higher Mg#, MgO, Ni, and Cr contents than the lower crust‐derived adakite‐like rocks. It is suggested that they were derived by variable degree of mixing between lower‐crustal melts and mafic magmas. Based on petrology and geochemistry features, the following evolution process are concluded. During the Neoproterozoic, metasomatic‐enriched mantle magma resulted from the bisubduction of oceanic plate; meanwhile, the crust thickened, and juvenile lower crust formed. During late Eocene, hot asthenosphere upwelled and K‐rich mafic magmas resulted from the decompression of delamination, followed by magmatism emplacing, crystallizing, and the forming of the Lianhuashan pluton. [ABSTRACT FROM AUTHOR]

• Zircon U–Pb ages range from 2753 ± 37 to 2476 ± 18 Ma in the Luxi Terrane. • Greenstone was derived from the Meso- to Neoarchean mantle contaminated by the crust. • TTGs were sourced from a Meso- to Neoarchean juvenile crust with older basement reworking. • Initial crustal growth at ca. 2750–2600 Ma, followed by more voluminous growth at ca. 2550–2450 Ma. Tonalite–trondhjemite–granodiorite (TTG) suites constitute dominant components of Precambrian continental crust and provide important insights into the crustal evolution history of the early Earth. Here we investigate a suite of TTGs and associated greenstones from the Luxi Terrane in the south–eastern part of the North China Craton (NCC). We present data from petrology, geochemistry, zircon U–Pb geochronology and Lu–Hf isotopes to characterize these rocks and understand their genesis. Mineral assemblage in the greenstones and TTGs suggests that the rocks have undergone amphibolite–facies metamorphism with regression under greenschist–facies. Zircon U–Pb data from the magmatic grains yield upper intercept ages of 2753 ± 37 and 2582 ± 40 Ma for greenstone, 2552 ± 13 Ma for TTG gneiss and 2476 ± 18 Ma for tonalite, and weighted mean 207Pb/206Pb age of 2507 ± 22 Ma for granodiorite. Lu–Hf isotope systematics show ε Hf (t) values ranging from −2.13 to 7.29 and crustal model ages (TC DM) in the range of 2603–3125 Ma for the TTGs, whereas the ε Hf (t) values are up to 8.53 with TC DM ages of 2644–3006 Ma for the greenstone. The results suggest that the protolith for the greenstone was derived from a Meso- to Neoarchean mantle contaminated by the crust source, whereas the TTGs were mostly sourced from juvenile crustal sources with reworking of older basement. The geochemical features of greenstone are similar to island arc basalt, with low Na 2 O, K 2 O and TiO 2 , low total rare earth elements (REEs) values, relative enrichment in light REEs and depletion in heavy REEs absence of obvious Ce anomaly, and negative Nb, Ta and Ti anomalies. The TTGs show similar features, except for the high K 2 O content and moderate total REEs values. We propose that the greenstone likely represent a part of the early and initial crustal growth at ca. 2750–2600 Ma, and the TTGs were generated subsequently at ca. 2550–2450 Ma. Our results are consistent with the previous models on the crustal growth models in the NCC and provide further insights into the Neoarchean to Paleoproterozoic tectonic history of the craton. [ABSTRACT FROM AUTHOR]

• Zircon U-Pb ages of 2776–2771 Ma mark a major phase of crust building. • Paleoproterozoic metamorphism dated as 1922–1915 Ma. • Amphibolite derived from partial melting of a metasomatic mantle source. • TTG gneiss derived from partial melting of juvenile lower crust. • Archean-Paleoproterozoic crustal accretion and reworking in the southern margin of the NCC. The North China Craton (NCC) preserves important records of Archean-Paleoproterozoic crustal evolution. Here we present results from petrology, geochemistry, zircon U-Pb dating and Lu-Hf isotopes of the Taihua Complex (THC) from the southern part of the NCC. Zircon U-Pb dating of the amphibolite yields the ages of 2776–2771 Ma representing the formation age, marking a major phase of late Archean crustal growth in the NCC. The 1922–1915 Ma ages represent the Paleoproterozoic metamorphism associated with the collisional assembly between the Eastern and Western Blocks. The amphibolites are characterized by low SiO 2 , Na 2 O + K 2 O, and Nb/Y, indicating a sub-alkaline basaltic protolith. These rocks show relatively high LILE/HFSE and LREE/HREE ratios, similar to E-MORB, low [Nb/La] PM , negative Nb-Ta anomalies and positive ε Hf (t) values indicating partial melting of a metasomatic mantle source. The TTG gneisses are characterized by high SiO 2 , Sr/Y, (La/Yb) N , Nb/Ta, Zr/Sm and Zr/Hf ratios, and low MgO, Cr, Ni, Y, Gd/Yb and Dy/Yb ratios, with positive Eu anomalies, indicating partial melting of juvenile lower crust with garnet-amphibolite residue. Our data are consistent with a tectonic setting within a volcanic arc in a convergent margin. Our study on the THC contributes to the Archean-Paleoproterozoic crustal accretion and reworking history along the southern margin of the NCC. [ABSTRACT FROM AUTHOR]