Early Precambrian Crustal Evolution in the Dengfeng Area, Henan Province (East China): Constraints from Geochemistry and SHRIMP U-Pb Zircon Dating
详细信息   
摘要


    

///Early Precambrian basement in the Dengfeng area, central Henan Province, is composed mainly of the Neoarchaean Dengfeng Group, Paleoproterozoic Songshan Group (“group” is used in the sense of regional map divisions, and does not necessarily have stratigraphic meaning) and Neoarchaean granitoids. Based on the data of this study and others, following conclusions can be drawn: 1) the Dengfeng Group was formed at the end of Neoarchaean (2.53～2.51 Ga); 2) different types of granitoids, together with the supracrustal rocks of the Dengfeng Group, were formed in a small time gap between 2.55 and 2.50 Ga; 3) the Wutai and Jishan granite-greenstone belts are similar in rock association and formation age to the Dengfeng granite-greenstone belt, all probably belonging to one and the same huge belt; 4) the deposition of the Songshan Group can be limited between 2.45 and 2.0 Ga and can be compared with the Gaofan Group (2.47～2.14 Ga) or the Hutou Group (2.14～2.08 Ga); and 5) the ca. 1.78 Ga Shichen monzosyenite is a product of intracrustal magmatism under an extensional tectonic regime following on from a compressive collisional orogeny earlier in the Paleoproterozoic in the North China Craton.  
    

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