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Research on the Zanhuang Complex has been one of the hotspots in the Neoarchean–Palaeoproterozoic tectonic evolution of the Trans‐North China Orogen (TNCO) in the North China Craton (NCC). Here, we present data from petrology, geochemistry, zircon U–Pb geochronology, and Lu–Hf isotopes on a suite of granite, diorite, TTG gneiss, and amphibolite in the Zanhuang Complex to characterize these rocks and understand their genesis. Zircon U–Pb data yield magmatic ages of 2,607 Ma for granite, 2,599 Ma for diorite and 2,561 Ma for TTG gneiss, with subsequent thermal event ages of 2,530 and 2,471 Ma. Lu–Hf isotopes show εHf(t) values ranging from 0.04 to 7.11 and crustal model ages of 2,700–3,100 Ma for the diorite, indicating a Meso‐ to Neoarchean mantle source with minor input of crustal components. The granite and TTG gneiss have the characteristics of volcanic‐arc granite, with low Sr/Y and (La/Yb)N, high Cr and Ni contents, positive Pb and K anomalies and negative Nb, Ta, P, and Ti anomalies. The amphibolite and diorite are similar to island arc basalt, with low K2O, Sr/Y, (La/Yb)N, and high FeOT, positive Pb anomaly, negative Nb, Ta, and Ti anomalies and absence of obvious Ce anomaly. These signatures indicate that these rocks were likely formed in a subduction setting. We have proposed a model of subduction–collision process in the TNCO, including subduction at ca. 2.70–2.55 Ga, arc–continent collision at ca. 2.55–2.45 Ga, extension and rifting at ca. 2.30–2.05 Ga, and continent–continent collision at ca. 1.90–1.75 Ga. Our results are consistent with the previous models on the tectonic evolution in the NCC and provide further insights into the Neoarchean–Palaeoproterozoic tectonic history of the craton. [ABSTRACT FROM AUTHOR]

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]