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The occurrence of extensional-related A-type granites with a high-K nature in some early Precambrian blocks hints a possible link with the orogeny, and may imply the ending of the orogenic processes and the beginning of craton stabilization. The newly recognized late Paleoproterozoic A-type granite, the Guijiayu pluton composed of monzogranites in the Xiaoqinling area of the southern margin of the North China Craton (NCC), is a promising locus to investigate the late Paleoproterozoic tectonic evolution of the NCC. LA-ICP-MS zircon U–Pb dating shows that the Guijiayu pluton was emplaced at ∼1.80 Ga. Petrologically, the Guijiayu granites contain perthite, annite and calcic amphibole but are lack of alkali mafic minerals. Geochemically, all the rocks are enriched in silicon and total alkali, and depleted in MgO, CaO and P 2 O 5 , with high FeOt/MgO, TiO 2 /MgO and 10,000 Ga/Al ratios and high HFSEs (i.e., Zr, Nb, Ce, Y) concentrations, as well as negative Eu, Sr, P and Ti anomalies. They are also characterized by high melting temperatures and metaluminous to weakly peraluminous natures. Taken together, the Guijiayu granites show an affinity to aluminous A-type granite. Their geochemical characteristics (e.g., obviously negative Eu and Sr anomalies), along with the low zircon ε Hf ( t ) values (−13.9 to −7.0) and whole-rock ε Nd ( t ) values (−5.81 to −5.65), indicate that the Guijiayu aluminous A-type granite was derived from partial melting of the crustal calc-alkaline granitoids dominated by the granodiorite of the Taihua Group in the study area. Combined with the regional data, especially for the identification of the clockwise P–T paths of Paleoproterozoic metamorphism in the southern margin of the NCC, even coeval granites and regional retrograde metamorphism in other areas in the NCC, it is most likely that the peak of continent–continent collision had finished in the study area at least before ∼1.80 Ga, and that the generation of the Guijiayu aluminous A-type granite was related to the underplating of mafic magmas in a post-collisional regime. [ABSTRACT FROM AUTHOR]

A-type granites are a spectrum of especial felsic rocks that are produced commonly within an extensional environment. They are rare before middle Paleoproterozoic but present abundantly since the late Paleoproterozoic, probably indicating a causal change of tectonics and geodynamic mechanism in the continental evolution of the Earth. An early Mesoproterozoic A-type granite belt was recognized in the southern margin of the North China Craton (NCC) in recent decades. The occurrence of this type of rocks indicates a possible spatial–temporal link between the tectonic evolution of the NCC and the breakup of the Columbia supercontinent during the Mesoproterozoic. The Zhangjiaping granitic pluton is located in the southern margin of the NCC and one part of the A-type granite belt. It can be divided into three zones according to their textural and compositional differences of the rocks with a gradually increasing degree of evolution inwards: wall zone, intermediate zone and core zone. LA-ICP-MS zircon U–Pb dating shows that it was emplaced at ca. 1.53 Ga. Petrologically, the Zhangjiaping granites contain perthite and calcic amphibole but are lack of alkali mafic minerals. Geochemically, all the Zhangjiaping granitic rocks show an affinity to fractionated aluminous A-type granites, with enrichment in silicon and total alkali, and depletion in MgO, CaO and P 2 O 5 with negative Eu, Sr and Ti anomalies, as well as high FeOt/MgO, TiO 2 /MgO and Ga/Al ratios and high HFSEs (i.e., Zr, Nb, Ce, Y) concentrations. Such signatures, along with their low ε Hf ( t ) values (−12.5 to −4.0) of all the granites from the Zhangjiaping pluton, obviously indicate that the Zhangjiaping aluminous A-type granites were derived from partial melting of the crustal calc-alkaline granitoids (i.e., the granodiorites of the Taihua Complex in the study area) and experienced fractional crystallization during magmatic evolution. Their generation would be related to the underplating of mafic magmas in an extensional regime. Integrated with regional data, the Zhangjiaping aluminous A-type granites were the products of anorogenic magmatism likely corresponding to the breakup of the Columbia supercontinent. [ABSTRACT FROM AUTHOR]

• A suite of ~1.6 Ga low-δ18O A-type granites was identified on the southern margin North China Craton. • The 18O-depletion A-type granites were derived from the remelting of preexisting hydrothermally altered basement rocks (i.e., Taihua Complex). • The formation of a low-δ18O source rocks and ~1.6 Ga A-type granites were related to the late Paleoproterozoic rifting. • The rifting might continue at least till ~1.6 Ga. A-type granites with 18O-depletion signatures are rather enigmatic as regards not only their typology and petrogenesis but also their rock-forming geodynamic mechanism. Here we report a suite of late Paleoproterozoic low-δ18O A-type granites from the Longwangzhuang pluton on the southern margin of the North China Craton. SIMS zircon U-Pb dating showed that the Longwangzhuang pluton was emplaced at 1613 ± 4 Ma. Combined with previous data, it is clear that the mineral components of Longwangzhuang granites are variable and consist of perthite, quartz, plagioclase, biotite and amphibole (calcic hastingsite, ferroedenite, and sodic ferrogedrite). Geochemically, they are metaluminous to peraluminous and have high alkali contents (K 2 O + Na 2 O > 8.76 wt%, K 2 O/Na 2 O > 1), FeOt/(FeOt + MgO) (>0.95) ratios, Zr + Nb + Ce + Y (>993 ppm) contents, and 10000 Ga/Al (>4.31) ratios, resembling A-type granites. In-situ oxygen isotope analysis displayed low zircon δ18O values between 4.0‰ and 4.9‰ with a weighted average of 4.4‰. Based on the Archean two-stage zircon Hf and whole-rock Nd model ages coupled with the low (La/Yb) CN ratios, negative anomalies of Eu and Sr, and high Zr saturation temperatures, and the presence of low pressures (3.3–5.7 kbar) amphiboles, the Longwangzhuang A-type granites were generated by "self-cannibalizing" pre-existing low-δ18O old rocks (i.e., the Taihua Complex) and emplaced at shallow depth. Combined with regional geological observations (i.e., coeval tuffites), a passive rift setting was the most plausible explanation for the generation of the late Paleoproterozoic low δ18O A-type granites on the southern margin of the North China Craton. Such a rifting could likely have lasted at least till 1.6 Ga. [ABSTRACT FROM AUTHOR]

The late Paleoproterozoic A-type granitoids are important for constraining of the lithotectonic and geodynamic processed involved in the creation of continental crust. The newly identified late Paleoproterozoic felsic extrusive rocks from the southwestern margin of the North China Craton (NCC) consist of rhyolites which show melting corrosion structure, autoclastic texture and fiber structure of mineral grains and have weighted mean SIMS zircon U Pb ages of 1794.7 ± 3.6 Ma to 1780.3 ± 5.6 Ma. The rhyolite samples show high SiO 2 (67.59–74.38 wt%) and K 2 O + Na 2 O (3.68–11.10 wt%), and low MgO (0.05–1.17 wt%), CaO (0.19–2.58 wt%) and P 2 O 5 (0.08–0.16 wt%). They display aluminous A-type granite/rhyolite geochemical compositions, such as high A/CNK (0.78–1.23), FeOT/(FeOT + MgO) (0.81–0.99) and 10000Ga/Al (2.32–4.03) ratios, and high Zr + Nb + Ce + Y (824–1272 ppm) concentrations, as well as high zirconium saturation temperatures (T Zr = 873–964 °C). These signatures, along with their low ε Hf (t) (−3.6 to −1.5) and ε Nd (t) values (−4.31 to −3.31) and old two-stage Hf model ages (T DM C = 2.70–2.57 Ga), indicate that the rhyolites were derived from partial melting of the Neoarchean felsic basement rocks. These volcanic rocks also have low zircon δ18O values ranging from 1.5‰ to 6.8‰, which were inherited from the Neoarchean 18O-depleted basement rocks that underwent high-T hydrothermal alteration, rather than resulted from contamination or later high-T water/rock interaction. The rhyolite rocks in this study, the earliest igneous rocks in the southwestern NCC after the Paleoproterozoic consolidation of the crystalline basement, were formed in a rift setting, marking the initial breakup of the Guyuan Rift in the southwestern NCC. The rhyolite rocks in combination with the Xiong'er volcanic rocks in the southern NCC mark the initial rifting of the NCC (Xiong'er Rift and Guyuan Rift) after cratonization (~1.85–1.8 Ga). The youngest retrograde metamorphism (1.80–1.79 Ga) in the NCC indicates that the transition from post-orogenic to intracontinental rift setting occurred at ca. 1.79 Ga. • The Baijiagou, Shizuizi and Baojiashan rhyolites formed at ca. 1.79 Ga. • Melting of pre-existing low δ18O rock produce the 18O-depleted rhyolites. • The rhyolites mark the initial rift of the southwestern NCC. • Transition from post-orogenic to intracontinental rift in NCC was at ca. 1.79 Ga. [ABSTRACT FROM AUTHOR]

To explore the applicability of MuLBSTA Score in COVID-19 patients, a retrospective analysis was performed on 330 cases of COVID-19 patients in Southeast Hospital of Xiaogan City, Hubei Province. The clinical characteristics of COVID-19 patients were described and multilobe infiltrate in CT, bacterial infection, lymphocyte count, smoke in history, history of hypertension, and age distribution in the population of mild and severe patients were analyzed. All included patients were scored according to the MuLBSTA early warning scoring system and its efficacy in early warning of severe symptoms was analyzed. CT feature of infiltration changes on multiple lobes, the absolute value of lymphocyte count of less than 0.8 × 10 9 , accompanied by bacterial infection, history of smoking, history of hypertension, and an age of greater than 60 years old were all statistically significant factors in patients with severe COVID-19. ROC curve analysis indicated that the sensitivity, specificity and accuracy of the early warning system were 0.651, 0.954 and 0.93, respectively. The MuLBSTA Score has a good early warning effect on severe COVID-19 patients., (Copyright © 2020 Elsevier Ltd. All rights reserved.)