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Daqingshan is located in the northwestern North China Craton where late Neoarchaean supracrustal rocks occur widely, but where magmatic zircon ages have rarely been reported for plutonic rocks. In this study, we report SIMS U–Pb zircon ages and Hf isotope, whole-rock element and Nd isotope compositions for 12 magmatic samples, including TTG, quartz monzonitic and monzogranitic gneisses, and meta-gabbroic and dioritic rocks. They have magmatic zircon ages of 2530–2469 Ma; some samples have ages of Nd(t) and in situ magmatic zircon ϵHf(t) values of +1.2 to +2.4 and −1.1 to +6.2, respectively. Quartz monzonite and monzogranite gneisses and gabbroic to dioritic rocks have similar Nd–Hf isotope compositions to the TTG gneisses. The absence of zircon >2.6 Ga in the early Precambrian rocks suggests that the Sanggan Group may have formed in an oceanic environment, whereas the TTG rocks formed as a result of partial melting of the basaltic rocks of the Sanggan Group under relatively low-pressure conditions. Combined with previous studies, the main conclusions are that in the Daqingshan area, late Neoarchaean magmatism was widespread, the late Mesoarchaean – early Neoarchaean was an important period of juvenile continental crustal growth, and the late Neoarchaean supracrustal and plutonic rocks most likely formed in an arc environment. These are common signatures for Neoarchaean crustal evolution throughout much of the North China Craton, and also globally.

Exposure of ultraviolet B (UVB) radiation is the main factor from the environment to cause skin photoaging. Lactobacillus rhamnosus ATCC 7469, is a probiotic strain with a good track record for enhancing human health. The present study conducted the impacts of heat-killed Lactobacillus rhamnosus ATCC 7469 (RL) on photoaging in vitro using mouse skin fibroblast (MSF) cells and human epidermal melanocytes (HEM) exposed to UVB. The results showed that (1) RL protected UVB-induced cytotoxicity relating to absorb UVB and reduce DNA damage. (2) RL exerted the anti-wrinkle impact involved in two aspects. Firstly, RL down-regulated MMP-1, 2, 3 expressions associating with MAPK signaling, resulting in the increased the protein expression of COL1A1, further booting type I collagen abundant thereby promoting the anti-wrinkle impact in MSF cells. Secondly, RL reduced ROS content, further decreasing oxidative damage relating to Nrf2/Sirt3/SOD2 signaling, thereby promoting the anti-wrinkle impact in MSF cells. (3) RL suppressed tyrosinase and TYRP-2 activity and/or levels associating with PKA/CREB/MITF signaling, thereby promoting anti-melanogenesis impact in HEM cells. In conclusion, our findings suggest that RL could reduce photoaging caused by UVB via anti-wrinkle and anti-melanogenesis properties and may be a potential anti-photoaging beneficial component, which is applied in the cosmetic industry.

A 37-year-old man presented with a 7-year history of low back pain. Magnetic resonance imaging revealed an intradural mass involving L5 vertebra impairment at the level of L4-L5. A L4-S1 laminectomy was performed. Pathology suggested the diagnosis of Solitary Fibrous Tumor/Hemangiopericytoma (SFT/HPCs). Unlike other spinal cord SFT/HPCs in lumbar area, we firstly reported the case with invasive growth and bone structure impairment. The patient had a good prognosis after 3-year follow-up. Complete resection should be achieved to reduce the recurrence.

The geomagnetic matching aided positioning system based on Iterative Closest Contour Point (ICCP) algorithm can suppress the accumulation error of the inertial navigation system and achieve the accurate positioning of the vehicle. Aiming at the problem that the ICCP algorithm is sensitive to heading error and easily mismatches in regions with similar geomagnetic general features, an improved ICCP matching algorithm based on geomagnetic vector is proposed. The ant colony algorithm is designed to improve the search strategy in a large probability range. The geomagnetic three-dimensional vector feature and the Hausdoff distance are employed as the objective function for multiple iterations, improving matching efficiency and accuracy. Simulation results show that compared with the traditional ICCP algorithm, the positioning error of the matching track, the heading error, and the matching time of the improved ICCP algorithm are reduced by 69.6%, 44.0% and 39.0%, respectively.

Purpose. OSA is closely associated with hypertension, and both epidemiological and experimental studies have confirmed that OSA is one of the most important independent risk factors for hypertension. The pathological mechanisms by which OSA causes hypertension are not well understood, and in this paper, we explored the molecular mechanisms by which OSA may mediate hypertension at the bioinformatics level. Materials and Methods. We downloaded disease-related datasets from the GEO public database, calculated the differential genes between the two groups of patients by the limma package, and then further constructed the WGCNA network based on the clinical characteristics of patients to explore the important regulatory genes in the disease. Subsequently, ssGSEA was used to explore the potential molecular mechanisms of disease progression and GSVA was applied to analyze the specific signaling pathways. Finally, we performed real-time quantitative PCR (qRT-PCR) to validate these pivotal genes. Results. Three genes were selected as target genes, namely, GPR179, RNF150, and JPH4. The results showed they were strongly correlated with immune cell content that high expression of the three core genes was associated with myogenesis, angiogenesis, oxidation, metabolism, and PI3K/AKT/mTOR pathways. qRT-PCR validated that all three genes have statistically significant differences between the OSA group and OSA combined with hypertension group. Conclusion. Our study provides new evidence for the potential molecular mechanisms of OSA combined with hypertensive disease as well as diagnosis and treatment.

ObjectivesWhetherKMT2A-PTD has a prognostic impact on patients with acute myeloid leukaemia (AML) is controversial. Therefore, we conducted a meta-analysis to assess the prognostic value ofKMT2A-PTD in patients with AML.MethodsEligibility criteria: we included studies concerning the prognostic value ofKMT2A-PTD in patients with AML.Information sources: Eligible studies were identified from PubMed, Embase, Medline, Web of Science, Cochrane Library and Chinese Biomedical Database. The systematic search date was 19 December 2020.Risk of bias: Sensitivity analysis was used to evaluate the stability and reliability of the combined results. Begg’s and Egger’s tests were used to assess the publication biases of studies.Synthesis of results: We calculated the pooled HRs and their 95% CIs for overall survival (OS) and event-free survival (EFS) by Stata V.12 software.ResultsIncluded studies: 18 studies covering 6499 patients were included.Synthesis of results:KMT2A-PTD conferred shorter OS in total population (HR=1.30, 95% CI 1.09 to 1.51). In the subgroup analysis,KMT2A-PTD also resulted in shorter OS in karyotypically normal AML patients (HR=2.72, 95% CI 1.83 to 3.61) and old AML patients (HR=1.93, 95% CI 1.44 to 2.42).KMT2A-PTD indicated no prognostic impact on EFS in total population (HR=1.26, 95% CI 0.86 to 1.66). However, in the sensitivity analysis,KMT2A-PTD resulted in poor EFS (HR=1.34, 95% CI 1.04 to 1.64) when deleting the study with a relatively obvious effect on the combined HR. In the subgroup analysis,KMT2A-PTD was associated with poor EFS in old AML patients (HR=1.64, 95% CI 1.25 to 2.03).ConclusionThe findings indicated thatKMT2A-PTD had an adverse impact on the prognosis of patients with AML in the total population, and the conclusion can also be applied to some subgroups including karyotypically normal AML and old AML patients.KMT2A-PTD may be a promising genetic biomarker in patients with AML in the future.Trial registration numberCRD42021227185.

New talaromydien A

Studies have explored the relation between serum uric acid (SUA) and carotid intima-media thickness (CIMT), but the relation remains controversial. The purpose of this study was to examine SUA concentration and its correlation with carotid artery atherosclerosis according to age group and gender. Subjects who underwent physical examinations at the First Affiliated Hospital of Chongqing Medical University from 2016 to 2020 were selected. Using traditional atherosclerosis risk factors as adjustment variables, the association between blood uric acid level and atherosclerosis was assessed by logistic regression analysis. A total of 15,843 subjects (73.90% men) were included, with an average age of 52 ± 12 years. The prevalence of increased CIMT was 9.51%, and the prevalence of plaque was 28.59%. Univariate analysis results showed that there were significant differences in the occurrence of increased CIMT and plaque among different SUA-level groups in both men and women (p0.0001). After adjustment for conventional cardiovascular risk factors, increased SUA level was significantly associated with an increased risk of carotid intima-media thickening. Correlation analysis in each age subgroup showed that CIMT was significantly associated with SUA in men ≥60 years old and women 45 to 60 years old or ≥60 years old (p0.0001). In conclusion, in both men and women, increased SUA levels are closely associated with increased CIMT. The age at which this association was observed was lower in women than in men; whether the lower age in women is due to changes in hormone levels between before and after menopause remains to be prospectively studied.

BackgroundThe study aimed to explore the factors influencing protective behavior and its association with factors during the post-COVID-19 period in China based on the risk perception emotion model and the protective action decision model (PADM).MethodsA total of 2830 valid questionnaires were collected as data for empirical analysis via network sampling in China. Structural equation modeling (SEM) was performed to explore the relationships between the latent variables.ResultsSEM indicated that social emotion significantly positively affected protective behavior and intention. Protective behavioral intention had significant direct effects on protective behavior, and the direct effects were also the largest. Government trust did not have a significant effect on protective behavior but did have a significant indirect effect. Moreover, it was found that government trust had the greatest direct effect on social emotion. In addition, we found that excessive risk perception level may directly reduce people’s intention and frequency of engaging in protective behavior, which was not conducive to positive, protective behavior.ConclusionIn the post-COVID-19 period, theoretical framework constructed in this study can be used to evaluate people’s protective behavior. The government should strengthen its information-sharing and interaction with the public, enhance people’s trust in the government, create a positive social mood, appropriately regulate people's risk perception, and, finally, maintain a positive attitude and intent of protection.

Objective: Uric acid is thought to be associated with the occurrence of atherosclerosis, which is closely related to cardio-cerebrovascular disease. However, the present study examined serum uric acid (SUA) and its correlation with carotid intima-media thickness (CIMT), which is a major issue. The purpose of this paper is to examine serum uric acid concentration and its correlation with carotid artery atherosclerosis according to age and sex groups.Methods: Individuals who underwent physical examinations at the First Affiliated Hospital of Chongqing Medical University from 2016 to 2020 were selected. The physical examination information of the subjects was recorded, and biochemical indexes such as blood uric acid levels were collected. The intima media thickness of the carotid artery was measured by ultrasound. Using traditional atherosclerosis risk factors as adjustment variables, the association between blood uric acid levels and atherosclerosis was assessed by logistic regression analysis.Results: A total of 15,843 subjects (73.90% male) were included, with an average age of 52±12 (20-92) years. The prevalence of CIMT thickened was 9.51%, and the plaque prevalence was 28.59%. Univariate analysis results showed that there were significant differences in CIMT thickening and plaque occurrence among different SUA level groups in both men and women (P430 μmol/L: OR=1.857, 95% CI: 1.264-2.73;P < 0.05. female: ≤210 μmol/L as the reference group, 260-310 μmol/L: OR=1.419, 95% CI: 1.059-1.901; 310-360 μmol/L: OR=1.432, 95% CI: 1.048-1.957; >360 μmol/L: OR=1.557, 95% CI: 1.113-2.177; P < 0.05). Correlation analysis in each age subgroup showed that CIMT was significantly associated with SUA in men ≥60 years old and women 45-60 years old and ≥60 years old (male: ≤220 μmol/L as the reference group, >430 μmol/L: OR=1.972, 95% CI: [1.2,3.238]. female: ≤210 μmol/L as the reference group, >360 μmol/L (45-60 years old): OR=1.77, 95% CI:[1.107,2.832]; > 360 μmol/L (≥60 years old), OR = 1.65, 95% CI: [1.067, 2.551]. P < 0.05).Conclusions: In both men and women, increased SUA levels are closely associated with thickened CIMT, which is associated with a higher risk of cardio-cerebrovascular disease. The age at which this association was observed in women was lower than in men, and whether this result is due to changes in hormone levels before and after menopause remains to be prospectively studied.

ECG biometric recognition has received plenty of attention in biometrics area. In recent years, various classical sparse representation and dictionary learning methods have been utilized in ECG biometric recognition. However, to produce better classification results, l P -norm is used to regularize the representation coefficients, which undoubtedly brings time cost problem. To overcome this limitation, our method, namely label-guided dictionary pair learning, aims to learn a projective dictionary and reconstructed dictionary jointly, which achieves signal representation and reconstruction simultaneously. Introduction of label information with each dictionary item and Fisher-like regularization on projective dictionary enforce discriminability during the dictionary learning process. Alternating direction method of multipliers is then exploited to optimize the corresponding objective function. Extensive experiments on two databases demonstrate that our method can achieve better performance compared with state-of-the-art ECG biometric recognition methods.

To evaluate the effects of moxibustion and acupuncture of Zusanli (ST 36) and Zhongwan (CV 12) acupoints on chronic atrophic gastritis (CAG) in rats, and to study the mechanisms behind their actions.Forty-four male Sprague-Dawley rats were induced with CAG by intragastric administration of 40% ethanol combined with free drinking of N-methyl-N'nitro-N-nitrosoguanidine and irregular feeding for 12 weeks, followed by daily treatment with moxibustion or acupuncture for 2 weeks. Histopathologic examination, Western blotting of cytokines [epidermal growth factor (EGF), EGF receptor (EGFR), extracellular signal-regulated kinase (ERK), phosphorylated ERK (p-ERK)], and 1H NMR-based metabolic profiling of gastric tissues were used to measure changes related to CAG modeling and treatment.Moxibustion and acupuncture at Zusanli (ST 36) and Zhongwan (CV 12) each relieved CAG-induced abnormalities in histopathology and cytokine expression of ERK and p-ERK. Only moxibustion treatment regulated the expression of EGF and EGFR. Metabolites that were increased in gastric tissue by CAG induction (alanine, nicotinamide adenine dinucleotide phosphate, uracil DNA glycosylase, lactate, glycerol and adenosine) were restored to normal levels after moxibustion treatment; acupuncture treatment only normalized the levels of adenosine monophosphate and glycerol.Our findings suggest that moxibustion or acupuncture at Zusanli (ST 36) and Zhongwan (CV 12) can significantly improve the condition of CAG in rats. These treatments exert their effects on CAG through different mechanisms.

New talaromydien A (1) and talaroisocoumarin A (2), together with nine known compounds (3 − 11), were isolated from a culture of the marine-derived Talaromyces sp. ZZ1616 in potato dextrose broth medium. Structures of the new compounds were elucidated based on their HRESIMS data, NMR spectroscopic analyses, the modified Mosher′s method, ECD, 13C NMR and optical rotation calculations. Talaroisocoumarin A showed antimicrobial activities with MIC values of 36.0 μg/mL against methicillin-resistant Staphylococcus aureus, 32.0 μg/mL against Escherichia coli, and 26.0 μg/mL against Candida albicans.

Mesoarchean and older potassic granites are important indicators of recycling of ancient continental crust early in Earth's history. This study of integrated whole rock and zircon geochemistry and geochronology reports the age and identification of the source materials of the > 200 km 2 Mesoarchean Tiejiashan-Gongchangling granite in the Anshan-Benxi area, North China Craton, the largest pre-Neoarchean granite domain in the craton. SHRIMP U-Pb zircon dating on 15 samples indicates the magmatic crystallization of the granites between 2.95 and 3.0 Ga and reveals a superimposed tectonothermal event at ~ 2.91 Ga. The granites are characterized by high SiO 2 and K 2 O, low CaO, FeOt, MgO and TiO 2 with peraluminuous features. They show large variations in (La/Yb) n and strong negative Eu and Ba anomalies and Nb, P and Ti depletions. Whole rock Nd and magmatic zircon Hf isotopic compositions show large variations, but with most having e Nd (t) and e Hf (t) values DM (Nd) and t DM (Hf) values varying from 3.3 to 3.9 Ga and 3.3 to 4.0 Ga, respectively. Magmatic zircons without very strong lead loss (discordance ≤ 20%) have δ 18 O values of + 3.14 to + 8.39. 3.3–3.7 Ga xenocrystic zircons occur in some samples. The granite formed as a result of recycling of Paleo- to Eoarchean continental material in an intracontinental environment, with little if any contribution from Mesoarchean mantle sources. The sources could be predominantly unaltered ancient gneisses, together with yet to be identified Paleo- to Eoarchean materials affected by early low temperature alteration (weathered rocks or clastic sediment).

There are different viewpoints on metamorphic and anatectic zircons recording ages of 2.45–2.48 Ga or even younger in some areas of the North China Craton where both late Neoarchean and late Paleoproterozoic tectono-thermal events are well developed. These are: 1) partial resetting of the U-Pb isotopic system in the late Neoarchean zircons, 2) metamorphism lasting from the late Neoarchean to the earliest Paleoproterozoic, and 3) earliest Paleoproterozoic metamorphism as separate different event. Western Shandong Province is an area where the late Neoarchean tectono-thermal event is widely developed but the late Paleoproterozoic event has not been identified. This provides an opportunity to understand the geological processes around the Archean-Proterozoic boundary. Based on a field study, we carried out SHRIMP U-Pb zircon dating on seventeen samples of ∼2.5 Ga old metamorphic and anatectic rocks, including tonalite, trondhjemite, granodiorite, gabbro, quartz diorite, granite and paragneiss with primary emplacement or depositional ages of 2.52–2.68 Ga. Anatectic zircons show some textural and compositional features: a) Homogenous or blurred oscillatory zoning, b) high U contents and low in Th/U ratios (commonly

Microtopography affects hydrological processes and forms different microhabitats. Our previous study uncovered that riparian zone microtopography created various microhabitats with different soil environments and runoff-infiltration patterns. However, how riparian microtopography and microtopography within the water area (waterfall and tributary) affects downstream water quality remains unclear. Therefore, water samples were taken almost monthly in both the main stream and the tributary, before and after waterfalls, and near the bottom of three microtopographic types from June 2016 to March 2017. Compared with the dry season, the fact that water quality worsened in the wet season and that there were positive correlations for nitrate (NO3-) between water and the corresponding soil samples suggested that the riparian-soil environment affected the adjacent water quality mainly in the wet season. Nevertheless, riparian microtopography did not influence water quality downstream because of the low rainfall frequency and the weak leaching process due to plant interception. In the wet season, both the tributary and the waterfall increased the dissolved oxygen in the water body and, therefore, lowered the risk of eutrophication. The tributary has two pathways for improving the water quality, by increased disturbance and flow velocity, while the waterfall only has the former. However, such effects were not significant in the dry season. We conclude that the application of microtopographic modification is useful in maintaining urban wetland water quality in wet seasons.

Incretin contains two peptides named glucagon-like peptide-1(GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). Drug therapy using incretin has become a new strategy for diabetic treatments due to its significant effects on improving insulin receptors and promoting insulinotropic secretion. Considering the fact that diabetes millitus is a key risk factor for almost all age-related diseases, the extensive protective roles of incretin in chronic diseases have received great attention. Based on the evidence from animal experiments, where incretin can protect against the pathophysiological processes of neurodegenerative diseases, clinical trials for the treatments of Alzheimer’s disease (AD) and Parkinson’s disease (PD) patients are currently ongoing. Moreover, the protective effect of incretin on heart has been observed in cardiac myocytes, smooth muscle cells and endothelial cells of vessels. Meanwhile, incretin can also inhibit the proliferation of aortic vascular smooth muscle cells, which can induce atherosclerogenesis. Incretin is also beneficial for diabetic microvascular complications, including nephropathy, retinopathy and gastric ulcer, as well as the hepatic-related diseases such as NAFLD and NASH. Besides, the anti-tumor properties of incretin have been proven in diverse cancers including ovarian cancer, pancreas cancer, prostate cancer and breast cancer.

A total of 106 marine microbial metabolites were evaluated for their antiproliferative activity against human lung cancer cells. Results showed that 23 compounds exhibited activity in inhibiting the proliferation of A549 and H157 cells with IC50 values ranging from 1.5 to 48.2 μM. Pyrrospirone F, chrysophanol, physcion, and purpuride G are the four most active compounds with IC50 values of 1.5–7.3 μM. Further investigation of purpuride G (a newly discovered sesquiterpene lactone) demonstrated its potent antiproliferative activity against six different lung cancer cells of A549, H157, H460, H1299, H1703, and PC9 with IC50 values of 2.1–3.3 μM. The antiproliferative activity of purpuride G against cancer cells is related to block cell cycle, induce apoptosis through regulating the apoptotic proteins Bcl-2 and Bax, and inhibit glycolysis by downregulating two key glycolytic enzymes of hexokinase 2 and pyruvate kinase M2.

Voluminous Neoarchean plutonic and supracrustal rocks are well developed in the Western Shandong Province of the North China Craton, which has been divided into a late Neoarchean crustally-derived granite belt, a middle to early Neoarchean ancient rock belt and a late Neoarchean juvenile rock belt. Earlier studies provided reconnaissance evidence for ∼2.60 Ga metamorphism in some areas. This study presents SHRIMP zircon U–Pb dating and O isotope analysis on nine metamorphosed igneous rock samples (gneissic tonalite, gneissic trondhjemite, gneissic quartz diorite and meta-gabbro) from the ancient rock belt. Magmatic zircons vary in age from 2.74 Ga to 2.60 Ga, whereas metamorphic and anatectic zircons vary in age from 2.63 Ga to 2.59 Ga, with an age peak of 2.61 Ga. In this study, we identified 2.69–2.67 Ga metamorphic zircons for the first time. Most of zircons, whether magmatic or metamorphic, have δ 18 O values of +4.5‰ to +6.5‰ (V-SMOW). However, the oldest tonalite sample with a protolith age of 2735 Ma has zircons showing low δ 18 O (V-SMOW) values, particularly in recrystallized domains and overgrowths. This suggests at least in local crustal extension and influx of meteoric water during the evolution of the rocks. Combined with data from earlier studies, we draw the conclusion that the Western Shandong Province experienced a regional tectono-thermal event at ∼2.60 Ga, as a result of high heat flow and crustal extension, perhaps caused by a mantle plume or mantle overturn activity. Therefore we conclude that 2.60 Ga can be regarded the break between early and late Neoarchean crustal accretion. The O isotope study indicates that in some cases, trondhjemitic leucosome was not derived from nearby gneissic tonalite, although they show a close relationship in outcrop.

Four new compounds, including three drimane sesquiterpenoids purpurides E–G (1–3) and one isocoumarin peniisocoumarin H (4), together with 15 known compounds, were isolated from the marine-sourced fungus Penicillium minioluteum ZZ1657. Their structures were elucidated by a combination of the HRESIMS data, extensive NMR spectroscopic analyses, and single crystal X-ray diffractions. Purpurides E (1) and F (2) are two N-acetyl- l -valine-conjugated drimane sesquiterpenoids and showed antimicrobial activities against methicillin-resistant Staphylococcus aureus, Escherichia coli, and Candida albicans with MIC values of 6–12 and 3–6 μg/mL, respectively. Purpuride G (3) showed antiproliferative activities against human glioma U251 and U87MG cells with IC50 values of 4.49 and 10.9 μM, respectively.

Marine natural products are important resources for discovering novel anticancer drugs. In this study, an extract prepared from the culture of a sea anemone-derived actinomycete Streptomyces sp. ZZ406 in soluble starch and casein-related liquid medium was found to have activity in inhibiting the proliferation of glioma cells and reducing the production of lactate in glioma cells. Chemical investigation of this active crude extract resulted in the isolation of four new compounds and seven known ones. Structures of the new compounds were determined by a combination of extensive NMR analyses, HRESIMS and MS-MS data, electronic circular dichroism calculation, chemical degradation, and Marfey’s method. New compound 1 showed potent activity against the proliferation of different glioma cells with IC50 values of 4.7 to 8.1 μM, high selectivity index (>12.3 to 21.3), and good stability in human liver microsomes. Western blot analysis revealed that compound 1 remarkably downregulated the expressions of several important glioma glycolytic enzymes. The data from this study suggested that compound 1 might have potential as a novel anti-glioma agent to be further investigated.

The North China Craton is an ideal place for studying the transition of the Earth's thermal structure and tectonics at the Archean–Proterozoic boundary due to its good preservation of the ~ 2.5 Ga tectono-thermal events. We report the discovery of a high-pressure mafic granulite from the Jiaodong Terrain in the North China Craton. The mafic granulite occurs as garnet–clinopyroxene–orthopyroxene–hornblende gneiss enclaves within a late-Archean trondhjemite–tonalite–granodiorite (TTG) gneiss. Typical high-pressure mineral assemblage of garnet–clinopyroxene–plagioclase–quartz ± rutile has been identified. Plagioclase + clinopyroxene ± orthopyroxene ± hornblende symplectite surrounding garnet (“white eye”) is also observed. Using the conventional geothermobarometry and the pseudosection modeling, a clockwise metamorphic P–T path with the peak conditions at ~ 17 kbar and ~ 880 °C was determined. Zircon U–Pb analyses (SHRIMP) on the overgrowth rim of zircon grains of two samples from the same outcrop yielded a metamorphic age of 2473 ± 6 Ma (MSWD = 0.8). The analyses on magmatic core gave a probable magmatic age of 2527 ± 12 Ma (MSWD = 1.9). The high-pressure granulite facies metamorphism corresponds to a collisional event between the ~ 2.5 Ga crust and ~ 2.9 Ga crust at the dawn of Paleoproterozoic in the North China Craton. It also represents a new but rare case of a subduction–collision tectonics at the Archean–Proterozoic transition and provides insight into the change of the Earth's thermal structure.

We present an integrated study of zircon U-Pb dating and O-Hf isotopic analyses combined with whole-rock geochemistry and Nd isotopic systematics on widespread late Neoarchean syenogranites (Qidashan Pluton) and other granitoids (granodiorite, quartz monzonite, monzogranite) in the Anshan-Benxi area, eastern North China Craton. All these rocks were emplaced at ca. 2.5 Ga according to SHRIMP zircon U-Pb dating and other indirect methods. The syenogranites are characterized by high SiO2 and K2O/Na2O and low CaO, FeOt, MgO, TiO2 and P2O5. However, they differ in trace element and REE compositions and can be roughly subdivided into two types. Type 1 syenogranite has strongly negative Eu anomalies and Ba depletion, with large variations of LREE to HREE differentiation; type 2 syenogranite has no negative Eu anomaly and Ba depletion. Other granitoids are also rich in K2O and show similar trace element and REE compositional features as the type 2 syenogranite. Most syenogranite samples have whole-rock eNd(t) values of –10.5 to –2.7 and tDM(Nd) ages of 2.96 to 3.90 Ga, whereas the other granitoids have eNd(t) values of –5.2 to –2.2 and tDM(Nd) ages of 2.95 to 3.19 Ga. Magmatic zircon from the syenogranites has eHf(t) values and Hf crustal model ages ranging mainly from –11.0 to +4.4 and 2.70 to 3.46 Ga, respectively; those from other granitoids have eHf(t) values and Hf crustal model ages of –16.0 to +2.4 and 2.81 to 3.72 Ga, respectively. All these rocks contain Meso- to Paleoarchean xenocrystic zircon grains with eHf(t) values and Hf crustal model ages ranging from –14.3 to +8.3 and 2.79 to 3.93 Ga, respectively. Decoupling of whole-rock Nd and Hf-in-zircon isotopes occurs in some samples. Most low-U magmatic zircon (U

Sensitive High-Resolution Ion Microprobe (SHRIMP) U-Pb analyses of zircons from Paleoarchean (~3.4 Ga) tonalite-gneiss called the Older Metamorphic Tonalitic Gneiss (OMTG) from the Champua area of the Singhbhum Craton, India, reveal 4.24-4.03 Ga xenocrystic zircons, suggesting that the OMTG records the hitherto unknown oldest precursor of Hadean age reported in India. Hf isotopic analyses of the Hadean xenocrysts yield unradiogenic 176Hf/177Hfinitial compositions (0.27995 ± 0.0009 to 0.28001 ± 0.0007; ɛHf[t] = −2.5 to −5.2) indicating that an enriched reservoir existed during Hadean eon in the Singhbhum cratonic mantle. Time integrated ɛHf[t] compositional array of the Hadean xenocrysts indicates a mafic protolith with 176Lu/177Hf ratio of ∼0.019 that was reworked during ∼4.2-4.0 Ga. This also suggests that separation of such an enriched reservoir from chondritic mantle took place at 4.5 ± 0.19 Ga. However, more radiogenic yet subchondritic compositions of ∼3.67 Ga (average 176Hf/177Hfinitial 0.28024 ± 0.00007) and ~3.4 Ga zircons (average 176Hf/177Hfinitial = 0.28053 ± 0.00003) from the same OMTG samples and two other Paleoarchean TTGs dated at ~3.4 Ga and ~3.3 Ga (average 176Hf/177Hfinitial is 0.28057 ± 0.00008 and 0.28060 ± 0.00003), respectively, corroborate that the enriched Hadean reservoir subsequently underwent mixing with mantle-derived juvenile magma during the Eo-Paleoarchean.

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Western Shandong Province is a typical area of the North China Craton (NCC) where Neoarchean plutonic and supracrustal rocks are widely distributed. Early studies documented that ∼2.7 Ga and ∼2.5 Ga magmato-tectono-thermal events are well developed in the area. Here we report SHRIMP U–Pb ages and Hf-in-zircon isotopic data from ten samples of different magmatic rock types including hornblendite, gneissic tonalite, gneissic trondhjemite and gneissic granite. Magmatic zircon grains have 207Pb/206Pb ages ranging from 2667 to 2598 Ma. Some rocks contain ∼2.5 Ga metamorphic rims and ∼2.7 Ga zircon cores. The magmatic zircon grains have ɛHf(t) values and Hf crustal model ages of −1.1 to +11.3 and 3.02–2.4 Ga, respectively. Combined with an earlier study, our main conclusions are that the middle Neoarchean rocks mainly occur together with early Neoarchean rocks in the northeastern portion of the central belt. Juvenile additions to continental crust and crustal recycling played important roles in the middle Neoarchean of western Shandong Province, and the entire Neoarchean tectonic evolution can be divided into middle to early Neoarchean (2.75–2.6 Ga) and late Neoarchean (2.6–2.5 Ga) events.

Eastern Shandong is one of the important early Precambrian areas in the North China Craton, where extensive 2.5, 2.7 and 2.9 Ga magmatic activities have been identified, followed by very strong late Neoarchean and Paleoproterozoic tectono-thermal events. We carried out SHRIMP zircon dating, Hf-in-zircon isotope analysis and a whole-rock geochemical study on ca. 2.9 Ga Mesoarchean magmatic rocks. These include gneissic diorite, gneissic quartz diorite, gneissic tonalite and gneissic high-Si trondhjemite and were identified in five new areas. All these rocks contain ca. 2.5 Ga metamorphic zircons. The dioritic and tonalitic rocks are enriched in large ion lithosphile (LIL) elements (K, Rb, Ba) and depleted in Nb and P with moderate to highly fractionated REE patterns, similar in chemical compositions to Archean TTG rocks worldwide. The high-Si trondhjemites are characterized by very high SiO2 and very low FeOt + MgO. The magmatic zircon grains from all these rocks are similar in their Hf isotopic compositions and have ɛHf(t) values ranging from + 1.3 to +9.9. Combined with previous work, our main conclusions are: (1) eastern Shandong underwent a major magmatic event at ca. 2.9 Ga; (2) diorites and tonalites formed by melting of thickened lower crust or the root of an oceanic plateau, whereas the high-Si trondhjemites were derived from melting of intermediate to felsic rocks; (3) the Mesoarchean (ca. 2.9 Ga) was a major period of juvenile crustal addition from the depleted mantle, earlier than the major crustal growth period at 2.7–2.8 Ga in the North China Craton; (4) the 2.7–2.9 Ga rocks underwent strong metamorphism at ca. 2.5 Ga, probably as a result of magmatic underplating.

The North China Craton (NCC) is characterized by major ∼2.5 Ga tectono-thermal events and is thus different from many other cratons worldwide where ∼2.7 Ga events are well developed. However, whole-rock Nd and Hf-in-zircon isotopic compositions of ∼2.5 Ga crustally derived granitoids reveal that they mainly formed through reworking of late Mesoarchean to early Neoarchean continental material. We review the spatial distribution, rock types, geochemical and Nd–Hf isotopic compositions of ∼2.7 Ga granitiods that are widely identified in the NCC, including eastern Shandong, western Shandong, Huoqiu, Hengshan, Fuping, Zanhuang, Zhongtiao and Wuchuan. These granitoids are mainly tonalitic in composition and frequently underwent strong metamorphism, deformation and anatexis. They show large variations in SiO 2 , total FeO, MgO and CaO, and can be subdivided into two types in terms of their REE patterns. More importantly, whole-rock Nd and Hf-in-zircon isotopic compositions indicate that the strong ∼2.7 Ga tectono-thermal event mainly involved juvenile additions to the continental crust. The early Neoarchean was the most important period for rapid production of new continental crust in the NCC. The main difference of the NCC from many other cratons worldwide is a strong and widespread superimposed tectono-thermal event at ∼2.5 Ga that stabilized the cratonic assemblage.

The Upper Wulashan “Subgroup” at Daqingshan in the Khondalite Belt of the Western Block of the North China Craton contains an Early Paleoproterozoic (2.5–2.45 Ga) supracrustal sequence, incorporating banded iron formations, which we refer to as the Daqingshan Supracrustal Rocks. They contain rounded to elliptical zircon grains that commonly show core–rim or core–mantle–rim structures and precise SHRIMP U–Pb dating of these domains allows the discrimination of a series of tectono-thermal events that straddle the Archean/Proterozoic boundary. Detrital zircon cores with oscillatory zoning have formation ages ranging from 2.55 to 2.50 Ga, indicating derivation from Late Neoarchean magmatic rocks. As a result of exhumation and erosion, these became incorporated in earliest Paleoproterozoic sediments that were deposited between 2.50 and 2.45 Ga and then underwent high-grade metamorphism at 2.45–2.40 Ga. This event variously recrystallized the cores into two main domains: a dark inner domain and a gray outer domain, as imaged in cathodoluminescence. The gray domains commonly show sector zoning and have Th/U ratios of 0.1–0.5, a feature commonly noted in zircons recrystallized under high-grade metamorphic conditions. Metamorphic mantles are generally more homogeneous in structure and have lower Th/U ratios (commonly