A precisely dated Proterozoic palaeomagnetic pole from the North China craton, and its relevance to palaeocontinental reconstruction

Abstract

A palaeomagnetic pole position, derived from a precisely dated primary remanence, with minimal uncertainties due to secular variation and structural correction, has been obtained for China’s largest dyke swarm, which trends for about 1000 km in a NNW direction across the North China craton. Positive palaeomagnetic contact tests on two dykes signify that the remanent magnetization is primary and formed during initial cooling of the intrusions. The age of one of these dykes, based on U–Pb dating of primary zircon, is 1769.1 ± 2.5 Ma. The mean palaeomagnetic direction for 19 dykes, after structural correction, is D = 36°, I = − 5°, k = 63, α95 = 4°, yielding a palaeomagnetic pole at Plat=36°N, Plong=247°E, dp = 2°, dm = 4° and a palaeolatitude of 2.6°S. Comparison of this pole position with others of similar age from the Canadian Shield allows a continental reconstruction that is compatible with a more or less unchanged configuration of Laurentia, Siberia and the North China craton since about 1800 Ma

Geochemistry and zircon ages of mafic dikes in the South Qinling, central China: evidence for late Neoproterozoic continental rifting in the northern Yangtze block

“…Such dikes are also associated with intrusive complexes (Baer and Reches 1987) or oceanic crust, i.e., in ophiolites (Baragar et al 1987). Mafic dike swarms in cratons record significant rifting events and can be used for reconstruction of continent assemblies (e.g., Halls et al 2000;Hou et al 2005;Kullerud et al 2006;Peng et al 2005Peng et al , 2007Peng et al , 2008Peng et al , 2011. In ancient continental orogens, mafic dikes may record phases of crustal weakness.…”

Oscillatory Sr isotopic signature in plagioclase megacrysts from the Damiao anorthosite complex, North China: Implication for petrogenesis of massif-type anorthosite

“…Intruding the basement rocks are numerous Paleoproterozoic anorthosite-mangerite, rapakivi granitic and granitic plutons (1.75 to 1.68 Ga; e.g., Ramo et al, 1995;Zhang et al, 2007;Zhao et al, 2009), forming a typical anorthosite-mangerite-charnockite-granite suite (AMCG; Emslie et al, 1994). In addition, mafic dike swarms with ages of~1.77 Ga are also common in the northern part of the North China Craton (Hall et al, 2000).…”

Age and geochemistry of the early Mesoproterozoic A-type granites in the southern margin of the North China Craton: Constraints on their petrogenesis and tectonic implications

“…1.6-1.2 Ga marked by widespread Mesoproterozoic continental rifting, anorogenic magmatic activities and mafic dyke swarms (e.g., Gao et al, 2008a;Hou et al, 2008;Li et al, 2009;Peng et al, 2013). Paleomagnetic and paleogeographic studies have suggested that the NCC was involved in the assembly and breakup of the Columbia supercontinent (Halls et al, 2000;Zhao et al, 2002a;Zhang et al, 2012a;Xu et al, 2014). In fact, other lines of evidence including stratigraphic, structural, geochemical, metamorphic and geochronological data have also lent further support to this proposition (Condie, 2002; http://dx.doi.org/10.1016/j.precamres.2016.07.018 0301-9268/Ó 2016 Elsevier B.V. All rights reserved.…”