A precisely dated Proterozoic palaeomagnetic pole from the North China craton, and its relevance to palaeocontinental reconstruction
A precisely dated Proterozoic palaeomagnetic pole from the North China craton, and its relevance to palaeocontinental reconstruction
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DOI：
10.1046/j.1365-246x.2000.00231.x
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发表时间：
2000-10
影响因子：
2.8
通讯作者：
H. Halls;Jianghai Li;D. Davis;Guiting Hou;Baoxing Zhang;X. Qian
中科院分区：
文献类型：
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作者：
H. Halls;Jianghai Li;D. Davis;Guiting Hou;Baoxing Zhang;X. Qian
本文利用精确定年的原始剩磁资料，以最小的长期变化和构造校正的不确定性，获得了华北克拉通北北西向延伸约1000 km的中国最大岩墙群的古地磁极位置。两个岩墙的古地磁接触试验均为阳性，表明岩体的逆冲磁化是主要的，是在岩体初始冷却过程中形成的。其中一条脉岩的年龄为1769.1 ± 2.5Ma。19个岩墙经构造校正后的平均古地磁方向为D = 36°，I = − 5°，k = 63，α95 = 4°，古磁极位置为Plat=36°N，Plong=247°E，dp = 2°，dm = 4°，古纬度为2.6°S。将这一极位与加拿大地盾上类似年代的其它极位进行比较，可以得到一个大陆重建，该大陆重建与劳伦提斯、西伯利亚和华北克拉通自大约1800 Ma以来或多或少保持不变的构造相一致
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