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The Shimian Neoproterozoic plutons are located on the western margin of the Yangtze Block and are important for reconstructing the tectonic environment of this region. We present in situ zircon LA–ICP–MS U–Pb geochronological and Hf isotopic analyses for the plutons, as well as whole‐rock major‐ and trace‐element compositions. The monzogranite and syenogranite yield concordant ages of 773.6 ± 5.6 Ma and 812.2 ± 1.8 Ma, respectively, which indicates that they formed during the Tonian of the Neoproterozoic. The samples have very similar geochemistry, with high SiO2 (71.45–75.46 wt%) and Al2O3 (12.38–14.36 wt%) contents. The samples have a geochemical characteristics typical of peraluminous A‐type granites, including high Ga/Al and Rb/Sr ratios and elevated contents of high‐field‐strength elements. The samples also display high Rb/Sr (13.9–23.0) and Rb/Nb (12.5–19.2) ratios. The monzogranite and syenogranite yield positive εHf(t) values (+1.6 to +9.4 and + 5.2 to +9.8, respectively) and T2DM ages of 1.54–1.22 Ga and 1.51–1.21 Ga, respectively, which indicates that they were derived from partial melting of Mesoproterozoic crust or contamination with upper mantle. We propose that the syenogranite and monzogranite formed in a syn‐orogenic extensional setting during the Tonian period and that continuous subduction was responsible for the Neoproterozoic magmatic activities. [ABSTRACT FROM AUTHOR]

• 2.56–2.33 Ga magmatism were revealed in the Taihua Complex (THC). • The formation of 2.56–2.50 Ga TTGs in THC was related to amalgamation of micro-blocks. • The formation of ∼ 2.35 Ga granitic rocks in THC was related to a worldwide rifting event. • A tectonic transition from compression to extension occurred during the late Neoarchean. • Multistage crustal growth, reworking and stabilization were record in the southern NCC. The Archean-Paleoproterozoic Taihua Complex, extending from east to west along the southern margin of the North China Craton (NCC), is an ideal window to understand the tectonic evolution of the early Earth. Here we present new data on petrology, zircon geochronology, whole-rock geochemistry and isotopes of TTGs, granitic gneisses and felsic leucosomes of migmatites from the Taihua complex in the Xiaoqinling area. Zircon LA-ICP-MS analyses of rocks yield the formation ages of 2564–2503 Ma for TTGs, 2481–2476 Ma for felsic leucosomes and 2359–2334 Ma for granitic gneisses, respectively. The zircon Lu-Hf isotopes suggest that crustal growth occurred in the late Neoarchean and crustal reworking occurred in the end of Neoarchean and the early Paleoproterozoic. The TTG gneisses are characterized by high Na 2 O/K 2 O, La/Yb, Sr/Y and low Nb/Ta ratios, and they were likely generated by partial melting of subducted juvenile oceanic crust with garnet or amphibole in residuals, a mechanism similar to the slab melting model. Both the felsic leucosomes and granitic gneisses have high SiO 2 contents and various Hf isotopic compositions, and they probably were formed in an extensional setting, attributing to partial melting as well as mixing of the preexisting TTG suite. Statistically, we report a major transitional phase in the tectonic milieu of the southern NCC from compression to extension during the late Neoarchean (ca. 2.57–2.42 Ga). The compressional tectonics can be attributed to amalgamation of micro-continental blocks during the late Neoarchean (ca. 2.57–2.5 Ga) as the leading period of crustal growth and associated multistage TTG magmatism. In contrast, the extensional phase occurred during the end of Neoarchean (ca. 2.5–2.42 Ga) that may represent the end of cratonic stabilization period and formation of large amounts of K-rich granitic rocks, widespread high-grade metamorphism and migmatites. Additionally, the formation of a large amount of crust-derived granites and mafic dykes during the early Paleoproterozoic in southern NCC reflect another stage (ca. 2.36–2.24 Ga) of crustal extension, which represents an episode of initial worldwide rifting events probably linking to the great oxygen event (GOE). Therefore, the present study proposes a new profile on multi-stage crustal growth/reworking and craton stabilization during Neoarchean-Paleoproterozoic period along the southern NCC, and provides useful insights on complex and heterogeneous evolutionary processes of early Earth. [ABSTRACT FROM AUTHOR]

Metamorphosed clastic rocks provide important constrains on the composition of upper continental crust. Here we report and characterize a sequence of Neoarchean paragneiss in association with migmatite from the Qixingtai area in Western Shandong Province (WSP) in the North China Craton (NCC), that represent metamorphosed moderate- to fine-grained clayey clastic rocks. The garnet from the paragneiss is characterized by nil or weakly compositional zoning. The biotite shows low TiO 2 content (<2 wt.%) and high Fe/[Fe + Mg] molar ratios (0.45–0.48). The P – T estimates suggest that the paragneiss sequence was metamorphosed at 5.5–5.7 kbar and 678–679 °C. The detrital zircons from the sillimanite garnet gneiss yield concordant 207 Pb/ 206 Pb ages from 2.78 to 2.53 Ga (discordance ≤15%), suggesting that the protolith sediments were deposited after 2.53 Ga. The overgrowth rims on the detrital zircons of the paragneiss and those from the leucosome of the migmatite show similar low Th/U values, moderate Th and high U and common lead contents, indicating that the metamorphic and anatectic zircons formed under fluid-rich conditions. The intrusive contact between the massive monzogranite and the banded migmatite suggests that the regional metamorphic/anatectic event occurred before the emplacement of the monzogranite. However, the upper intercept ages, defined by the overgrowth rims of the pre-existing zircons from the leucosome, are broadly similar to those of the crystallization of the magmatic zircons from the monzogranite within errors at ∼2.50 Ga. The paragneiss exhibits SiO 2 contents in the range of ∼58 wt.% (garnet gneiss)–∼70 wt.% (sillimanite gneiss), and negative correlations with Al 2 O 3 (23.4–15.4 wt.%), TiO 2 (0.90–0.35 wt.%), MgO (4.5–1.1 wt.%), FeO t (8.3–2.6 wt.%) and Cr (382–131 ppm). The REE patterns also show a systematic change from garnet gneiss to sillimanite gneiss. In trace element discrimination diagrams, the paragneiss plots between the end-members of komatiite/basalt and TTG/granite, suggesting that the sediments sourced from a mixture of ultramafic–mafic and felsic protoliths. Combined with the geochronological data, we suggest that the 2.75–2.71 Ga komatiite–tholeiite sequence of the Taishan association and TTGs in the central terrane and the 2.56–2.53 Ga TTGs in the southwestern part of the WSP as the potential provenance for the clastics. The protolith of the paragneiss in the Qixingtai area belong to the sedimentary sequence of the Taishan association. Spatially associated coeval arc-like assemblage and other geological evidence suggest that, (1) the metasediments were likely deposited in a back arc basin, (2) the upper amphibolites-facies metamorphism, constrained by the mineral assemblages in the paragneiss, might be related to the closure of the basin, and (3) the generation of large volumes of matured K-rick continental crust occurred not earlier than 2.53 Ga in the WSP granite–greenstone belt. [ABSTRACT FROM AUTHOR]

Abstract: Voluminous tonalite–trondhjemite–granodiorite (TTG) magmas were emplaced in the Huai’an Complex of North China Craton (NCC) during the Neoarchean. Here we present the geochemical characteristics of these rocks and identify low-Al (LAl) and high-Al (HAl) types of trondhjemites within the TTG suite. The LAl group displays high silica (SiO2 =77–80wt.%), and low Al2O3 contents (11.06–11.89wt.%), a strongly peraluminous (A/CNK=1.16 and 1.19) composition and enrichment in HREE (LaN/YbN =4 and 5, GdN/YbN =0.35 and 0.9). Their low Rb (13 and 28ppm), Th (0.3 and 7.0ppm), relatively high Na2O/K2O values (3.6 and 4.1) and MgO (0.63 and 0.68wt.%) with moderately high Mg# (36 and 53), suggest crystallization from a primitive source. The HAl group is characterized by relatively low SiO2 (67.22–71.57wt.%) and high Al2O3 contents (16.35–16.41wt.%) with trace element contents and distribution patterns closely comparable to those of Archean high-Al TTGs. Our geochemical data do not favor a direct genetic link between the LAl and HAl trondhjemite groups. The zircon U–Pb data reveal that the LAl and HAl groups represent coeval intrusions at ca. 2.55–2.5Ga. In situ analysis of Hf isotopes in the zircons (εHf=+5.6 to +10, and TDM =2462–2595Ma), together with the geochemical features of the low-Al trondhjemites suggest that they were generated under relatively low pressure (<8kbar), through low degree partial melting of a newly accreted amphibolitic crust. Taking into consideration the contemporaneous (2.55–2.50Ga) high-Al TTGs widely exposed in the Huai’an Complex, we suggest that the low-Al trondhjemites were formed by intraplating of mantle-derived magmas, and the coeval high-Al TTGs were produced by partial melting of a thickened lower crust, triggered by underplating. Our study attests to a major episode of Neoarchean crustal growth in the NCC, and remelting induced by underplating and intraplating of mantle-derived magmas. [Copyright &y& Elsevier]

Abstract: The crustal growth and stabilization of the North China Craton (NCC) relate to three major geological events in the Precambrian: (1) a major phase of continental growth at ca. 2.7Ga; (2) the amalgamation of micro-blocks and cratonization at ca. 2.5Ga; and (3) Paleoproterozoic rifting–subduction–accretion–collision tectonics and subsequent high-grade granulite facies metamorphism–granitoid magmatism during ca. 2.0–1.82. The major period of continental growth during 2.9–2.7Ga in the NCC correlates with the global growth of Earth''s crust recognized from other regions. The enormous volume of tonalite–trondhjemite–granodiorite (TTG) rocks and associated komatiite-bearing magmatic suites developed during this period possibly suggest the manifestation of plume tectonics. The cratonization of the NCC at the end of Neoarchean at ca. 2.5Ga (Archean–Proterozoic boundary) through the amalgamation of micro-blocks was accompanied by granulite facies metamorphism and voluminous intrusion of crustally-derived granitic melts leading to the construction of the basic tectonic framework of the NCC. Several Neoarchean greenstone belts surround the micro-blocks and represent the vestiges of older arc–continent collision. The next major imprint in the NCC is the Paleoproterozoic orogenic events during 2.35 -1.82 Ga which involved rifting followed by subduction -accretion -collision processes, followed by plume-triggered extension and rifting, offering important insights into modern-style plate tectonics operating in the Paleoproterozoic. Extreme crustal metamorphism and formation of high pressure (HP) and ultra-high temperature (UHT) orogens during 1950–1820Ma accompanied the subduction–collision process and the suturing of continental blocks within the Paleoproterozoic supercontinent Columbia. Multiple subduction zones with opposing subduction polarity promoted the rapid assembly of crustal fragments of the NCC and their incorporation into the Columbia supercontinent. The HP and HT-UHT granulites demonstrate two main stages of metamorphism at ca. 1.95–1.89Ga and at ca. 1.85–1.82Ga, exhuming the basement rocks from lowermost crust level to the lower-middle crust level. With the emplacement of extensive mafic dyke swarms associated with continental rifting, and the intrusion of anorogenic magmatic suites, the evolution of the NCC into a stable continental platform was finally accomplished. [Copyright &y& Elsevier]

Abstract: The North Qinling terrain reveals a different geological history from the North China block to the north and the South Qinling micro-continental block to the south. The timing of events and geochemical features of the North Qinling terrain are essential for understanding the evolution of the Qinling orogenic belt that joins the North and South China blocks. This study presents detrital zircon ages and Hf isotopic compositions from the Guandaokou Group, a cover sequence of the North China block, and from the Kuanping Group, an upper basement sequence of the North Qinling terrain. The youngest detrital zircon U–Pb ages constrain the initiation of sedimentation in the Guandaokou Group to 1.85Ga and the maximum depositional age of the Kuanping Group to ~640Ma. Zircon U–Pb ages and Hf data testify to a major phase of magmatism in the North Qinling terrain at ~1000–900Ma. The magmatic rocks were largely produced from reworking of early Paleoproterozoic (~2.5–2.0Ga) crust with minor contribution of late Paleoproterozoic (~1.7Ga) juvenile material. This age record differs in time from the two important thermal events of ~1.85Ga and ~2.5Ga, widely manifested in the North China block. The North Qinling terrain can thus be regarded as a separate micro-continent with a pre-Neoproterozoic evolution different from that of the North China block. The final assembly of the North Qinling terrain to the North China block took place after about 640Ma. [Copyright &y& Elsevier]

Abstract: The Sariwon sills are distributed in the Pyongnam basin at the center of the Korean peninsula, eastern part of the North China Craton. These sills are up to 150m in thickness and up to more than 10km in length. Baddeleyite grains separated from a ~50m thick sill give a SIMS 206Pb–207Pb age of 899±7Ma (MSWD=0.34, n=14), which is interpreted to be the crystallization age of this sill. Zircon grains from the same sill gives a lower intercept U–Pb age of ~400Ma, which is likely a close estimation of the greenschist-facies metamorphism of this sill. The Sariwon sills are dolerites and have tholeiitic compositions. They show enrichment of light rare earth element concentrations (La/YbN =1.4–2.8) and are slightly depleted in high field strength elements (e.g. Nb, Zr, and Ti), in comparison to neighboring elements on the primitive-mantle normalized spidergram. The whole rock εNdt (t=900Ma) values are around −2, whereas in-situ εHft (t=900Ma) values from zircon grains vary from −25 to +8. They are similar to the coeval sills in other parts of the North China Craton, e.g., the Chulan sills (Xu-Huai basin, Shandong peninsula) and the Dalian sills (Lv–Da basin, Liaodong peninsula). These sills possibly originated from a depleted mantle source (e.g., asthenosphere), rather than from the ancient lithospheric mantle of the North China Craton, and have experienced significant assimilation of lithospheric materials. The strata and sills in the Xu-Huai, Lv–Da and Pyongnam basins are comparable; moreover the three basins are geographically correlatable based on Neoproterozoic geographical reconstruction. We therefore propose that there is a Xu-Huai–Lv–Da–Pyongnam rift system along the south-eastern edge of the North China Craton during Neoproterozoic (~900Ma), with the closure of the rift at ~400Ma as a result of a continent-margin process. It is possible that this southeastern margin of the NCC did not face the inland in the configuration of the supercontinent Rodinia. [Copyright &y& Elsevier]

Major and trace elements and Sr–Nd–Pb isotope data are reported for Cretaceous mafic dikes from the Jiaodong Peninsula, eastern China. These dikes range from medium-K and high-K calc-alkaline to shoshonitic or ultrapotassic rocks, which are characterized by high MgO (Mg#=71–53) and Cr (177–1012 ppm) and low TiO2 (0.55–0.90 wt.%), total Fe2O3 (5.12–9.48 wt.%) and CaO (4.99–9.94 wt.%). Overall, they are enriched in the large ion lithophile elements (LILE, e.g., Rb, Ba, Sr) and light rare earth elements (LREE), depleted in the high field strength elements (HFSE, e.g., Nb, Ti, P), and possess uniform initial 87Sr/86Sr (0.7094–0.7114) but relatively wide ranges of Nd [&epsiv;Nd (T)=−10.1–−17.0] and Pb (206Pb/204Pb=16.75–18.03) isotopic ratios, implying a magma origin from enriched but heterogeneous mantle sources. These geochemical and isotopic characteristics can be explained by the vein-plus-peridotite melting model, with amphibole- or phlogopite-bearing pyroxenite veins that reside in refractory lithospheric mantle beneath the North China Block. Such a vein-enriched mantle source formed by multiple metasomatic events, which we infer to have resulted from subduction-related processes that may have occurred in the Late Archean and Mesoproterozoic. The mafic dikes constitute a member of the widespread Mesozoic magmas emplaced in the North China Block as a result of regional lithospheric extension. [Copyright &y& Elsevier]