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The debate on the role of vertical versus horizontal tectonism in Archean cratons is intimately linked to the initiation of plate tectonics. The dome-and-keel architecture has been considered as a consequence of vertical tectonism. Although such a structural pattern is documented in some Mesoarchean and older cratons, such as the Kaapvaal and Pilbara cratons, whether it also occurs in Neoarchean cratons is poorly constrained. Determining the kinematics, structural evolution, and the timing of these structures is crucial in understanding how the tectonic behavior operated during the evolution of the early Earth. The North China Craton, especially its eastern part, is a Neoarchean continental block and preserves typical greenstone- granite rock assemblages. Detailed structural mapping reveals that the Anziling area (east China) is characterized by a typical dome structure without significant reworking by later deformation. The dome is in tectonic contact with a supracrustal rock assemblage that is now the dip-slip Shuangshanzi ductile shear zone. In the supracrustal rocks, compositional layers are folded into upright isoclinal folds. Meanwhile, along the shear zone, foliation varies from NNW to SW with sub-vertical dip. Mineral stretching lineations indicate a sinistral shear sense with a slightly oblique-slip component in the north, but show NWW-directed and SW-directed steep dip-slip shear in the west and south, respectively. Kinematic indicators imply that the granitic dome formed through a vertically upward movement accompanied by an uneven clockwise rotation. The supracrustal rocks sank downwards to form the regional keel structure. Structural data suggests that the Anziling area is a typical dome-and-keel structure. U-Pb zircon dating on pre-, syn-, and post-tectonic dykes indicate that the dome-and-keel structure formed at 2530-2500 Ma, and was intimately related to the emplacement of tonalite-trondhjemite-granodiorite granitoids. New data from this study suggest that until the late Neoarchean, the vertical tectonism was still a dominant tectonic regime that was operating in the eastern North China Craton. [ABSTRACT FROM AUTHOR]

Abstract: The NE–SW-trending Hepu–Hetai shear zone extends for about 480km along the boundary between Guangdong and Guangxi provinces in the southern part of South China. Field mapping and kinematic analyses indicate that the zone is characterized by dextral ductile strike-slip deformation, with an estimated displacement along the fault zone in excess of 500km. Studies of synkinematic phengite and gas–liquid inclusions in quartz within mylonite suggest that the ductile shear deformation occurred under medium temperature/pressure conditions of the greenschist facies, and 40Ar/39Ar analyses of muscovite yield ages of 213–195Ma. Based on these data and Late Paleozoic–Mesozoic paleogeographic data for southern China, we propose that the Hepu–Hetai shear zone originated via the penetration of the Yunkai Promontory of South China into Indochina during the Triassic. [Copyright &y& Elsevier]