A precisely dated Proterozoic palaeomagnetic pole from the North China craton, and its relevance to palaeocontinental reconstruction |
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| Authors: | Henry C Halls Jianghai Li Don Davis Guiting Hou Baoxing Zhang Xianglin Qian |
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| Institution: | Department of Geology, University of Toronto at Mississauga, Mississauga, Ontario, Canada L5L 1C6. E-mail:; Department of Geology, Peking University, Beijing 100871, People's Republic of China ;Jack Satterly Geochronological Laboratory, Royal Ontario Museum, Toronto, Ontario, Canada, M5S 2C6 |
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| 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, α 95 = 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 |
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| Keywords: | China dykes palaeomagnetism Palaeoproterozoic U–Pb geochronology |
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