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苏格兰当巴(Dunbar)下石炭统含钙砂岩组12个采样点的热退磁结果,显示一致的稳定磁化方向:偏角D=196°,倾角 I=-45°,α_(95)=4.3。侵入其中的一条20m厚的石炭系岩脉,其6个采样点的热退磁结果显示不同的磁化方向:D=195°,I=15°,α_(95)=10.7。 本文研究烘烤效应,论证了上述两个磁化方向均为原生。这与现存的对不列颠群岛该时期古地磁方向的看法矛盾。其原因可能是:1.以往的数据解释不可靠,特别是重磁化问题;2.构造原因;3.持续相当时间的异常地磁场。 对比纬度相似的太平洋夏威夷群岛熔岩流的“点记录”,本文针对当巴提出一种磁化模式:各有关古地磁磁化成分可能均产生于同一地质时代. 火成岩的尖晶石相方向,最可能为原生.它在古地磁分析中应给以较大权重.
The thermal demagnetization results at 12 sampling sites in Dunbar Carboniferous sandstone group in Dunbar show consistent directions of stable magnetization: declination D = 196 °, dip I = -45 ° and α 95 = 4.3. Intruding into a 20-m-thick Carboniferous dyke, the thermal demagnetization results at six sampling points show different directions of magnetization: D = 195 °, I = 15 °, α 95 = 10.7. In this paper, we study the baking effect and demonstrate that the above two magnetization directions are all primary. This contradicts the existing view of the paleomagnetic direction of the British Isles during this period. The reasons may be: 1. The past data interpretation is not reliable, especially the heavy magnetization problems; 2. The reasons for the structure; 3. Abnormal geomagnetic field for a considerable period of time. Comparing the “point record” of lava flows in the Pacific Hawaii archipelago with similar latitudes, this paper proposes a magnetization model for the Dangba region: all the related paleomagnetic geomagnetic components may have originated in the same geologic age, and the spinel phase direction of igneous rocks is most likely to be It should be given more weight in paleomagnetic analysis.