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In the Mesoproterozoic and Neoproterozoic, the North China Craton (NCC) underwent long-lived sedimentation with minor volcanism in the Yan-Liao Rift forming the Mesoproterozoic Changcheng, Jixian and Qingbaikou Groups in sequence. The basal boundary age of the Lower Changcheng Group indicates the initial time of the NCC as a stable cratonic block and can be used to make correlations among several representative basins worldwide. Recent studies have debated the initial depositional time of the Changcheng System, which is the key to understanding the Proterozoic tectonic evolution of the NCC. This study documented the xenotime and monazite from the lowermost Changzhougou and Chuanlinggou Formations of the Changcheng Group. The monazite grains from the Chuanlinggou Formation yielded U–Pb ages between 1810 Ma and 2500 Ma, which are comparable to the detrital zircon U–Pb ages in the same formation, indicating their detrital origin. Xenotime mostly occurs as overgrowths on the detrital zircon grains, supporting a post-depositional origin. The low U content of the Changzhougou Formation's xenotimes indicates a hydrothermal origin. Its peak age of 1570 ± 15 Ma may indicate a hydrothermal event. The xenotime from the Chuanlinggou Formation is characterized by a high U content and a REE pattern with a nonexistent or weak negative Eu anomaly and a higher Gd/Yb ratio, implying a diagenetic origin. These xenotime overgrowths yielded a wide age variation, even on a single grain, due to prolonged xenotime precipitation. The oldest population of 1716 ± 3 Ma is interpreted as the minimum depositional age of the Chuanlinggou Formation. The lowest boundary of the Changchengian System must be older than 1716 Ma. This work demonstrates that diagenetic xenotime could better constrain the depositional time; however, extensive systematic research is required, especially with higher spatial resolution and more diagenetic xenotime grains.

The Mesoproterozoic Yanliao diabase sills are widespread at the northern margin of the eastern North China Craton (NCC) and provide a means to examine the evolution of the NCC lithospheric mantle from amalgamation to breakup and dispersal of the Columbia supercontinent. Here, we report new baddeleyite U–Pb ages, whole-rock geochemical and Sr–Nd–Hf isotopic data, and baddeleyite Hf isotopes for diabase rocks from different sills, which provide insights into the source and petrogenesis of the magmas and the Mesoproterozoic evolution of the NCC. In situ baddeleyite U–Pb dating yields consistent ages of ca. 1320 Ma for these sills, suggesting coeval emplacement. The diabase samples are all tholeiitic and have high TiO2 and total Fe2O3, and low alkali contents. They have variable Mg# values and major- and trace-element contents but uniform primitive-mantle-normalized trace-element patterns, with weak enrichment in light rare-earth elements (LREEs) and large-ion lithophile elements (LILEs), and depletion in high-field-strength elements (HFSEs). The whole-rock and in situ isotopic contents of the diabase samples are homogeneous, with initial 87Sr/86Sr ratios of 0.7032–0.7049, eNd(t) values of −0.7 to +3.1, eHf(t) values of +0.8 to +3.7, and baddeleyite eHf(t) values of +1.9 to +7.2. All of these geochemical features suggest that these rocks were derived from high-degree partial melting of a fertile lithospheric mantle source at the depth of spinel stability, with subsequent olivine, clinopyroxene, and plagioclase fractionation. This lithospheric mantle was distinct from the previous Archean to Paleoproterozoic cratonic lithospheric mantle beneath the NCC, indicating a refertilization process by upwelling asthenospheric materials during the Mesoproterozoic. This upwelling, together with other Mesoproterozoic magmatism at the craton margin, would have significantly modified the subcontinental lithospheric mantle of the eastern NCC during the Mesoproterozoic, thereby increasing the susceptibility of the craton to subsequent Mesozoic decratonization.

Simultaneous in situ U–Pb dating, trace element and Hf isotopic analyses have been carried out on detrital zircons obtained from sandstones in the Neoproterozoic Jing’eryu Formation from the Eastern Block, North China Craton (NCC), with the aim of constraining the ages of magmatic and metamorphic events and hence the Precambrian crustal evolution of the NCC. Two groups of zircons, i.e., magmatic and metamorphic in origin, have been identified based on cathodoluminescence images, zircon Ti-temperatures and Th/U ratios. Zircon U–Pb dating shows two main magmatic events with ages of 2.55–2.47 Ga and 1.80–1.70 Ga, and four metamorphic events, with ages of 2.51–2.48 Ga, 1.96–1.90 Ga, 1.87–1.85 Ga and ∼1.80 Ga in the NCC. No zircons with ages of ∼3.8 Ga have been identified in this study, indicating either these were covered at the time of deposition or the limited presence of 3.8 Ga rocks in the NCC. The Hf isotopic data show the ∼2.5 Ga magmatic zircons have variable ɛHf(t) values, including both positive and negative values and with crustal model ages of 2.7–2.9 Ga, which can be interpreted to indicate mixed sources for their parental rocks, i.e., ancient crust (3.8 Ga or 3.3 Ga) and depleted mantle, implying significant continental crustal growth at ∼2.5 Ga. However, Paleoproterozoic magmatic zircons all have negative ɛHf(t) and Archean Hf model ages, suggesting that their parental rocks were formed from recycled Archean materials. The widespread ∼2.5 Ga metamorphism in the Eastern Block, coupled with extensive ∼2.5 Ga magmatism and crustal growth, are consistent with a mantle plume beneath the Eastern Block of the NCC during the Neoarchean. Whereas, a progressive increase in ∼1.85 Ga metamorphic zircon westward across the Eastern Block toward the Trans-North China orogen is best explained by collision between the Eastern and Western blocks at this time.

The basement characteristic of the Chinese Altai is not firmly constrained, which has strictly hindered our understanding of the early crustal growth in the region. The presence of Precambrian detrital zircons in metasedimentary rocks and xenocrystic zircons in granitoids may be regarded as evidence for the existence of unexposed old basement rocks, but can also be explained as detritus originally derived from a nearby cratonic fragment. This paper reports detrital zircon U–Pb and Hf isotopic data for both low- and high-grade metasedimentary rocks from the Chinese Altai. Zircons from these samples have similar age patterns and Hf isotopic compositions. They are characterized by an overwhelming dominance of Neoproterozoic-Early Paleozoic ages, with prominent peaks around 465–542 Ma and ɛHf(t) values varying from −25 to +15. Besides, a few zircons cluster at 1.8–2.0 Ga and sparse ones yield discordant ages around 2.3–2.6 Ga, and both give negative ɛHf(t) values between 0 and −28. Combined with previous results in the region, our data suggest that low- and high-grade metasedimentary rocks most likely derived from similar provenances. These data, plus some xenocrystic zircon ages from the granitoid rocks, are quite comparable with the age patterns of the micro-continents and arc terranes in western Mongolia. The zircon population of 440–580 Ma is dominant for gneissic granitoids within the Neoproterozoic–Early Paleozoic terranes in western Mongolian and the Chinese Altai. The Precambrian zircons (>540 Ma) resemble those from old rocks preserved in the Tuva-Mongolian (TM) block and its adjacent arc terranes. Therefore, we suggest that old zircons in the Chinese Altai more likely represent the detritus recycled from western Mongolia. Moreover, information from the TM-derived Precambrian zircons, combined with previous palaeomagnetic constraints, favors northern India as the potential origin for the TM block, from which a small micro-continent drifted northwards and incorporated into the CAOB in a time interval from the Neoproterozoic to Early Paleozoic. Accordingly, the crustal growth of the CAOB in western Mongolia and the Chinese Altai could be outlined by a single accretionary system, and secular amalgamation of magmatic arcs around a Precambrian micro-continent can account for the accretionary history of the region in the Early Paleozoic time.

The North China Craton is one of the few places in the world where >3.8 Ga crustal material exists, since zircons of this age have been found in the Baijiafen and Dongshan gneisses from Anshan in northeastern China. However, it has been questioned whether any 3.8 Ga rock exists in the area, since various younger zircons exist within single rock samples, and zircons with age of ∼3.8 Ga are few and can be interpreted as inherited in origin. A study of zircons using combined cathodoluminescence imaging and SHRIMP U–Pb dating indicates that the Baijiafen and Dongshan gneisses record several stages of granitic magmatism. The oldest magmatic event is recorded by a zircon with an age of 3887 ± 5 Ma, with a subsequent magmatic event at 3.8 Ga (3808 ± 24, 3798 ± 30, 3802 ± 11 and 3799 ± 6 Ma), confirming the existence of 3.8 Ga materials in the area. The next magmatic event took place at ∼3.6–3.7 Ga. However, all samples contain younger zircons with ages of 3.1–3.3 Ga, although they contain a few zircon grains with ages of ∼3.6–3.8 Ga. The 3.1–3.3 Ga zircons show typical igneous oscillatory zoning and do not show any evidence that were produced by metamorphism, indicating that these samples were emplaced at 3.3 and 3.1 Ga, respectively and the zircons with older ages are interpreted as inherited in origin. The exposure of 3.8 Ga rock is therefore much smaller than previously thought. In situ zircon Hf isotopic analyses indicate that these granitic rocks were derived from juvenile crust with age peaks of crustal growth at ∼3.4, 3.6 and 3.9 Ga, there is no evidence for existence of crustal material older than 4.0 Ga.

The eastern part of the North China Craton contains large volumes of Late Archean hornblenditic, tonalitic, dioritic, granodioritic and granitic rocks. LA-ICPMS zircon U–Pb dating of three plutons from eastern Hebei, eastern North China Craton, record emplacement ages of 2526–2515 Ma and metamorphic ages of 2500–2490 Ma for the diorite, granodiorite, and monzogranite and 2440 Ma for the K-feldspar granite. Hornblendites have high MgO (8.6–10.6 wt.%), Cr (674–1126 ppm), Ni (125–159 ppm) and V (224–315 ppm) at low (basic) silica contents (SiO2 = 45.7–49.0 wt.%). They are enriched in light rare earth elements (LREEs) and large ion lithophile elements (LILEs) and depleted in high field strength elements (HFSEs), with positive ɛNd(t) values (+1.2 to +2.0), indicating they were derived from an enriched mantle source. The monzogranites have high Sr and Ba contents and Sr/Y and La/Yb ratios, low Y and HREEs abundances, and positive ɛNd(t) and zircon ɛHf(t) values with Nd and Hf model ages less than 3.0 Ga, reflecting that they were derived from partial melting of a juvenile lower crust at high pressure. However, the K-feldspar granites, with low Sr and Ba concentrations and high HREE and Y contents, are considered to have originated from partial melting of juvenile crustal materials at shallow crustal levels. The diorites and granodiorites have variable major and trace element concentrations. Magmatic zircons from these rocks have heterogeneous ɛHf(t) values but record uniform homogeneous U–Pb ages, indicating they resulted from mixing of mafic and felsic magmas, coupled with fractional crystallization. Because of the widespread distribution of Late Archean magmatism and evidence for magma mixing, possibly related to mafic magma underplating, it appears likely that this event in the eastern North China Craton may relfect mantle plume activity, that resulted in significant growth of continental crust during the Late Archean.

A combined study of zircon U–Pb and Lu–Hf isotopes, mineral O isotopes, whole-rock elements and Sr–Nd isotopes was carried out for Neoproterozoic volcanics and granites from the eastern part of the Jiangnan Orogen in South China. The results are used to test controversial models of petrogenesis (plume-rift, slab-arc and plate-rift) for similar ages of magmatic rocks in South China. Zircon U–Pb dating yields two groups of ages at ∼780 and ∼825 Ma, respectively, corresponding to syn-rift and pre-rift magmatic events in response to supercontinental rifting. Both volcanic and granitic rocks show trace element features similar to those of arc-derived igneous rocks, but with more significant enrichment in large ion lithospheric elements relative to oceanic arc basalts. They have positive ɛHf(t) values of 3.6–6.3 for zircons, with Hf model ages of 1.12–1.21 Ga. This indicates reworking of late Mesoproterozoic juvenile crust for the origin of the Neoproterozoic magmatic rocks. Thus, oceanic arc magmatism would occur in the late Mesoproterozoic, with remarkable production of juvenile crust at the southeastern margin of the Yangtze Block. Because of the tectonic collapse of arc–continent collision orogen in the pre-rift stage, S-type magmatic rocks were generated by burial and anatexis of juvenile arc-derived crust to form the pre-rift episode of granodiorites and volcanics. In the syn-rift stage, the volcanics formed by reworking of arc-derived sedimentary rocks whereas the granite was generated by melting of the pre-rift igneous rocks. Emplacement of evolved felsic magmas along the rift tectonic zone would cause subsolidus high-T meteoric-hydrothermal alteration, resulting in varying δ18O values for minerals from the volcanic and granitic rocks. Therefore, the plate-rift model is advanced to account for petrogenesis of all Neoproterozoic magmatic rocks in South China, with lithospheric extsension as the driving force of supercontinental rifting. Partial melting due to arc-continent collision, orogenic collapse and supercontinental rifting is also proposed as a mechanism for the chemical differentiation of continental crust towards the felsic composition.

An integrated study of geochronology and geochemistry was carried out for Neoproterozoic intrusions at Xiaofeng in the Yangtze Gorge. The results are used to provide constraints on their origin, with potential resolution to hotly debated models concerning the source and process of contemporaneous igneous rocks in South China. The Xiaofeng intrusions are composed of felsic–mafic dykes and their wall-rock granitoids in an area of

To understand the connection between continental cratonization and global tectonothermal event is essential for recognizing the formation and evolution of continental crust. Paleoproterozoic is an important era with occurrence of megascale tectonomagmatism in the world, but it has been intriguing whether they also influenced the oldest continent in South China. In order to decipher the nature of Paleoproterozoic event in South China, a combined study of zircon U-Pb dating, Hf and O isotope analyses was carried out for metasediments and amphibolite from the Kongling terrane, the only Archean microcontinent outcropped in South China. U-Pb ages of 1.97 ± 0.03 Ga were obtained with low Th/U ratios of 0.01–0.14, indicating that the ages are a record of Paleoproterozoic metamorphic event. 18 O values of ∼11‰ and ∼8‰ were measured for quartz from the metasediments and garnet from the amphibolite, respectively, suggesting that their sources experienced supracrustal recycling. eHf(t) values of about −6.5 and model Hf ages of about 3.0 Ga were acquired for zircons from the metapelites, suggesting an Archean source. Thus a response to the Paleoproterozoic global tectonothermal event in South China is reworking of Archean continental nucleus. Compared with Archean rocks at Kongling, abrupt changes in K2O/Na2O, REE and other trace elements are observed in the Paleoproterozoic metasedimentary rocks. This is interpreted to reflect a change in upper crustal composition at the Archean–Proterozoic boundary. A survey of Paleoproterozoic ages throughout the Yangtze Block suggests that metamorphic event and subsequent magmatic activity occurred in the north, but only magmatic activity in the south. Both metamorphic and magmatic activities are associated with formation of a unified basement responsible for cratonization of the Yangtze Block. This provides a geodynamic connection between the formation of this craton and the global tectonomagmatism in the Paleoproterozoic, marking continental accretion by arc-continent collision orogeny during assembly of the supercontinent Columbia.

A combined study of geochronology and geochemistry was carried out for Neoproterozoic granodiorites at the southeastern margin of the Yangtze Block in South China. The results demonstrate that sedimentary rocks derived from juvenile crust were melted to form strongly peraluminous granite in an arc-continent collision zone, resulting in continental growth. LA-ICPMS zircon U-Pb dating yields two groups of age at 824 ± 6 and 882 ± 16 Ma, respectively. From CL images, the young zircons are new grains or rims of homogeneous structure with magmatic zoning, whereas most of the old ages occur in cores or as single xenocrysts. The granodiorites show high A/CNK ratios of 1.38–1.89 and strong negative Nb and Ta anomalies as well as high δ 18 O values of 11.9–14.0‰ for quartz and 8.1–10.2‰ for zircon, pointing to a supracrustal origin characteristic of S-type granites. On the other hand, they have positive ɛ Hf ( t ) values of 3.4 ± 1.6 to 5.4 ± 2.6 for zircon, neutral ɛ Nd ( t ) values of −2.06 to 0.02 and low to medium initial 87 Sr/ 86 Sr ratios of 0.7033–0.7087 for whole-rock, indicating a magmatic source with significant components of juvenile crust similar to I-type granites. Relatively refractory minerals like zircon, garnet and quartz retain their magmatic O isotope ratios, whereas the other minerals, such as K-feldspar, plagioclase and biotite that show O isotopic disequilibria when paired with quartz, suffered different degrees of post-magmatic alteration at subsolidus temperatures. On the basis of element and isotope geochemistry, we interpret the 882 ± 16 Ma zircons as being inherited from arc-derived igneous rocks, and the 824 ± 6 Ma zircons as having crystallized from an anatectic crustally-derived magma. Arc-continent collision is inferred to have taken place at ca. 900 ± 20 Ma during assembly of the supercontinent Rodinia. Subsequent to weathering of juvenile crust in the back-arc basin, low-maturity sedimentary rocks were deposited from about 880 to 830 Ma between the Yangtze and Cathaysia Blocks. Extensional collapse of the collisional orogen at about 830–820 Ma is suggested as a geodynamic mechanism for burial and melting of the sediments of juvenile crust to produce the S-type granodiorites. As a result, the granodiorites are characterized by the features of both S- and I-type granites, and thus testify to the short-term recycling of juvenile crust with significant contributions to continental growth. The syn- and post-collisional magmatism may be a basic mechanism to result in compositional evolution from arc crust to continental crust.

The North China Craton (NCC) is proposed to have formed by collision between the Western and Eastern blocks at ∼1.85 Ga. However, the detailed history of the individual blocks remains unsolved. In the Eastern block, the Paleoproterozoic volcano-sedimentary rocks are mainly exposed along its eastern margin, and are referred to as the Liaohe Group in the Liaodong Peninsula of Liaoning Province and as the Guanghua, Ji’an and Laoling Groups in the Tonghua area of southern Jilin Province. The Guanghua and Ji’an Groups are characterized by the occurrence of volcanic rocks, whereas the Laoling Group is composed of clastic sediments and carbonates. Zircon U–Pb isotopic dating by LA-ICP-MS and SHRIMP methods indicates that the Guanghua and Ji’an Groups were formed between 2.1 and 2.0 Ga, but that the rocks of the Laoling Group may have formed in two episodes at 2.5–2.2 and 2.0–1.9 Ga, respectively. The present data indicate that the Ji’an, Laoling and Liaohe Groups are chaotic, without a common stratigraphy, with intense deformation making it difficult to identify original layering and contact relationships. Combined with age data from rocks intrusive into the sequence, the Paleoproterozoic tectonic evolution of the Liaoning–Jilin area can be related to collision and extension between the Liaonan block to the south and the Longgang block to the north. Extension in the Longgang block occurred at 2.12–1.98 Ga and was represented by eruption of the Guanghua mafic volcanic rocks. However, extension in the Liaonan block is expressed by 2.16–2.09 Ga A-type granites and ∼2.12–1.98 Ga volcano-sedimentary rocks of the Ji’an Group. These two blocks collided at ∼1.93–1.90 Ga, resulting in a clockwise metamorphic P – T path recorded in the N. Liaohe–Laoling Groups, followed by ∼1.85 Ga post-collisional evolution expressed by anticlockwise metamorphic P – T paths and immense granitic intrusions in the S. Liaohe–Ji’an Groups. Therefore, it is suggested that the collision between the Longgang and Liaonan in the Eastern block of the NCC occurred a little earlier than ∼1.85 Ga, when the NCC amalgamated by collision of the Western and Eastern blocks.

The presence or absence of Paleoarchean crust in different continents provides an important basis for a comparison of their growth histories. Since the finding of ca. 3.8 Ga detrital zircon in the North China craton by means of SHRIMP U–Pb dating, it has been a question whether the Yangtze craton, one of the two major blocks constituting the basement of China continent, also contain Paleoarchean crustal relicts. It is generally accepted that the basement of the Yangtze craton mainly formed in the Paleoproterozoic, with only minor Archean rocks in ages of 2.5–3.3 Ga. A combined study of zircon U–Pb dating and Hf isotope analyses for the Kongling migmatite and gneiss from this craton reveals the existence of ca. 3.5 Ga rocks. The zircon U–Pb ages are divided into three groups: ∼3.2 Ga in cores, ∼2.9 Ga in most grains and ∼2.0 Ga in rims. Both ∼3.2 Ga cores and ∼2.9 Ga grains have negative ɛ Hf ( t ) values of −1.6 and −4.0, respectively. Mantle-like δ 18 O values of 5.6–5.8‰ were obtained for the zircons, precluding a significant input by sedimentary source component for the magmas that are responsible for protolith of the Kongling metamorphic rocks. From the Hf model ages of these zircons, about 3.5 Ga crustal relicts are speculated to occur in the Kongling rocks. This provides the first demonstration for the existence of Paleoarchean rocks in the Yangtze craton. Thus the early evolutionary history of the Yangtze craton may resemble the North China craton that has crustal relicts with the minimum ages of 3.5 Ga. These Paleoarchean rocks resided in the crust of the Yangtze craton for at least several hundreds of million years before remelting, probably leaving some clues to be traced and verified. Paleoproterozoic U–Pb ages of 1.8–2.0 Ga are identified in magmatic and metamorphic rocks in the Yangtze craton, providing a likely connection of this craton with the North China craton with respect to assembly and breakup of the supercontinent Columbia during the late Paleoproterozoic.