Understanding the composition, formation and evolution of the oldest continental crust is crucial for comprehending the mechanism and timing of crustal growth and differentiation on early Earth. However, the preservation of the ancient continental crust is limited due to extensive reworking by later tectonothermal events. In the Lulong area of eastern Hebei, abundant ca. 3.8–3.4 Ga detrital zircons of the fuchsite quartzite have been previously identified. Nonetheless, the provenance and Hf isotopic compositions of the fuchsite quartzite remain unclear. In this study, we present new detrital zircon ages and Hf isotopic for the fuchsite quartzite in the Lulong area to establish the timing of deposition, the provenance and the regional stratigraphic relationship. Zircon U-Pb dating indicates that the fuchsite quartzite was deposited between 3.3–3.1 Ga and most grains were sourced from the 3.8 Ga TTG gneisses and Paleoarchean magmas. Field investigations and regional correlations reveal that the fuchsite quartzite from the Lulong area is equivalent to that of the Caozhuang area. Zircon Hf isotopic data from eastern Hebei Province (Lulong and Caozhuang areas) and Anshan and Xinyang areas indicate that the oldest crustal growth event of North China Craton occurred in the Hadean.

Petrological, geochronological, and geochemical analyses of mafic rocks in northern Liaoning were conducted to constrain the formation age of the Proterozoic strata, and to further study the source characteristics, genesis, and tectonic setting. The mafic rocks in northern Liaoning primarily consist of basalt, diabase, gabbro, and amphibolite. Results of zircon U-Pb chronology reveal four stages of mafic magma activities in northern Liaoning: the first stage of basalt (2209 ± 12 Ma), the second stage of diabase (2154 ± 15 Ma), the third stage of gabbro (2063 ± 7 Ma), and the fourth stage of magmatic protolith of amphibolite (2018 ± 13 Ma). Combined with the unconformity overlying Neoproterozoic granite, the formation age of the Proterozoic strata in northern Liaoning was found to be Paleoproterozoic rather than Middle Neoproterozoic by the geochronology of these mafic rocks. A chronological framework of mafic magmatic activities in the eastern segment of the North China Craton (NCC) is proposed. The mafic rocks in northern Liaoning exhibit compositional ranges of 46.39–50.33 wt% for SiO₂, 2.95–5.08 wt% for total alkalis (K₂O + Na₂O), 6.17–7.50 wt% for MgO, and 43.32–52.02 for the Mg number. TiO₂ contents lie between 1.61 and 2.39 wt%, and those of MnO between 0.17 and 0.21 wt%. The first basalt and the fourth amphibolite show low total rare earth element contents. Normalized against primitive mantle, they are enriched in large ion lithophile elements (Rb, Ba, K), depleted in high field strength elements (Th, U, Nb, Ta, Zr, Ti), and exhibit negative anomalies in Sr and P, as well as slight positive anomalies in Zr and Hf. The second diabase and the third gabbro have similar average total rare earth element contents. The diabase shows slight negative Eu anomalies (Eu/Eu* = 0.72–0.88), enrichment in large ion lithophile elements (Ba), depletion in Rb, and slight positive anomalies in high field strength elements (Th, U, Nb, Ta, Zr, Hf, Ti), with negative anomalies in K, Sr, and P. The gabbro is enriched in large ion lithophile elements (Rb, Ba, K), depleted in high field strength elements (Th, U, Nb, Ta, Zr, Hf), and exhibits positive anomalies in Eu (Eu/Eu* = 1.31–1.37). The contents of Cr, Co, and Ni of these four stages of mafic rocks are higher than those of N-MORB. The characteristics of trace element ratios indicate that the mafic rocks belong to the calc-alkaline series and originate from the transitional mantle. During the process of magma ascent and emplacement, it is contaminated by continental crustal materials. There are residual hornblende and spinel in the magma source of the first basalt. The other three magma sources contain residual garnet and spinel. The third gabbro was formed in an island arc environment, and the other three stages of mafic rocks originated from the Dupal OIB and were formed in an oceanic island environment. The discovery of mafic rocks in northern Liaoning suggests that the Longgang Block underwent oceanic subduction and extinction in both the north and south in the Paleoproterozoic, indicating the possibility of being in two different tectonic domains.

1. Introduction Earth exhibits a distinct bimodal distribution of continental and oceanic crust, a feature that differentiates it from other terrestrial planets in the solar system (Dilek et al., 2008; Dhuime et al., 2015). The continental crust plays a critical role in sustaining Earth's habitable surface conditions and climatic equilibrium (Lee et al., 2016; Rozel et al., 2017; Huang et al., 2021), while also serving as a significant repository of mineral resources (Rudnick and Gao, 2014; Tang, 2020). However, the continental crust is frequently subjected to significant destruction or reformation through subsequent weathering, erosion, and tectonic processes (Sobolev and Brown, 2019; Zhu et al., 2021; Cawood et al., 2022; Zhao et al., 2024), with only approximately 7% of the Archean crust remaining preserved across thirty-five ancient cratons (Rudnick and Gao, 2014; Wan et al., 2023). Furthermore, ancient cratons serve as repositories of numerous valuable pertaining to tectonic evolution, metamorphism, magmatism and metallic deposits (Sandiford, 2004; Moyen et al., 2006), which play crucial roles in sustaining the planet's resource base and habitability, and provide essential insights into the transition from pre-plate tectonic regimes to modern plate tectonics on Earth (Hamilton, 2011; Zhang et al., 2014; Gerya et al., 2015; Hastie et al., 2016; Cawood et al., 2018; Windley et al., 2021; Zhao et al., 2022, 2025). Systematic studies on ancient cratons are essential, as they would enhance our understanding of global Precambrian geology and contribute to the exploration of early Earth evolution. We therefore propose the Research Topic entitled "The World's Ancient Cratons: Tectonics, Metamorphism, Magmatism and Mineralization" in Frontiers in Earth Science. A total of seven papers focusing on magmatism, metamorphism, and tectonic evolution within ancient cratons have been published in this Research Topic (Figure 1). Among these, four studies document the Paleoproterozoic metamorphic, structural, and magmatic evolution of the Khondalite Belt within the North China Craton. One study focuses on the Paleoproterozoic evolutionary history of the Jiao-Liao-Ji Belt. One study examines the metamorphosed supracrustal rocks and the associated Neoarchean tectonic regime of the eastern Hebei terrane within the Eastern Block of the North China Craton. One paper is related to the structural and metamorphic characteristics of the basement rocks in the Gida Ayana area of western Ethiopia. The brief introductions of the seven papers included in this Research Topic are summarized below. FIGURE 1 Spatial distribution of major cratons in the world 2. Summary of papers Hu et al. conducted a comprehensive review of field investigations, petrological analyses, zircon U-Pb dating, whole-rock geochemical studies, and electron probe mineral thermobarometric data derived from garnet-bearing pyroxenite and serpentinite-like dunite within the ultramafic rocks of the east-west oriented Khondalite Belt, North China Craton. The hornblende pyroxenite and serpentinized dunite in the Wuchuan area were emplaced approximately 1.9 Ga. The ages of 2.2 Ga and 2.5 Ga obtained from the surrounding garnet-K-feldspar gneiss and garnet-plagioclase two-pyroxene granulite represent the regional metamorphic age and the protolith depositional age of the Khondalite Belt, respectively. Tectonic analysis indicates that these ultramafic rocks formed during the post-orogenic extensional stage. The ultramafic rocks formed under conditions of 767.93°C and 4.61 kbar, indicating a medium-pressure, high-temperature metamorphic environment. Furthermore, the lack of granulite-facies metamorphism induced by the intrusion of these ultramafic rocks suggests that the granulite-grade metamorphism observed within the Khondalite Belt is not directly associated with the post-orogenic extensional processes in the Inner Mongolia-Northern Hebei orogenic belt. Wu et al. employed zircon and monazite geochronology in conjunction with thermodynamic modelling to elucidate the retrograde metamorphic evolution of medium-pressure (MP) pelitic granulites within the Qianlishan Complex, Khondalite Belt, North China Craton. The results demonstrate that all MP pelitic granulites exhibit comparable clockwise pressure-temperature (P-T) paths, characterized by well-constrained post-peak P-T conditions ranging from 775°C to 825°C and 4.9 to 6.5 kbar. Zircon and monazite U-Pb dating results constrain the metamorphic ages of the pelitic granulites at ca. 1.93 Ga, which indicate that a peak-pressure metamorphic event occurred between 1.96 and 1.94 Ga, followed by a period of decompression and retrograde cooling around 1.93 Ga. Furthermore, these findings provide support for the hypothesis that a continent-continent collision occurred in the Khondalite Belt approximately 1.95 Ga, followed by a rapid slab-breakoff at shallow depths, which induced the exhumation of pelitic granulites in the western Khondalite Belt to mid-crustal levels and their subsequent cooling at around 1.93 Ga. Qiao et al. carried out field-based structural analysis and U-Pb geochronological investigations on the Helanshan ductile shear zones and Qianlishan ductile shear zones located within the western segment of the Khondalite Belt. A suite of monazite, titanite, and apatite U-Pb ages ranging from 1904 to 1801 Ma collectively constrain the timing of shear zone activity within the western Khondalite Belt. Furthermore, this study highlights that the post-collisional orogen-parallel ductile shear zones within the Khondalite Belt developed during the time interval of approximately 1.90-1.80 Ga. Wang et al. conducted a comprehensive study of representative meta-mafic and felsic rock assemblages from the Daqingshan Complex within the Khondalite Belt of the North China Craton. The zircon U-Pb dating results indicate that the meta-mafic and felsic rock assemblages yield crystallization ages...