DIPOLE AND NONDIPOLE FIELDS OF THE GEOMAGNETIC FIELD ON THE BASIS OF PALAEOINTENSITIES OF THE BRUNHES VOLCANIC ROCKS.

研制了实验仪器，并在第一年对测试样品进行了测量。交变磁场消磁器具有恒定增减场速率的最大输出120mT。这一恒定为100mT/60秒，因为较高的速率往往会导致较小的手臂。手臂是与NRM或TRM平行获取的，以进行比较。这样的臂可以校正各向异性效应的NRM或TRM强度。在最高温度下加热时间为10min。20min。分别在第一次和第二次加热中。样品采集自日本大仙火山、秘鲁安第斯火山区和大同单生火山(中国)。它们都是在布鲁内斯时代形成的。肖氏方法的双重加热导致32个样品中有13个样品成功。根据测量的古烈度和倾角计算的VDM，在以往的报告中显示了围绕平均VDM的分裂分布。这意味着地球发电机强度的分布可能比古地磁学家以前提出的分布更复杂。利用松山-布鲁内斯转变的沉积记录，研究了非酒窝/偶极子磁场中的相对强度变化。这些记录是从日本博索海相沉积物中获得的。频谱分析表明，过渡场的短周期变化非常显著，可能达到10^2年的量级。

The experimental instruments were developed and used in the measurents of the test samples in the first year. The alternating field demagnetiser has a 120mT maximum output with a constant rate of increasing and decreasing fields. This constancy is of 100mT/60sec because the higher rate tends to result in a smaller ARM.The ARM is acquired in parallel to the NRM or TRM which is compared. Such an ARM can correct the NRM or TRM intensity for the anisotropy effects. The heating time at the top temperature is 10min. and 20min. in the first and the second heating, respectively. The samples were collected from Daisen Volcano (Japan), Andean volcanic region (Peru), and Datong monogenetic volcanoes (China). All of them were formed in the Brunhes epoch. Double heating of the Shaw method results in the success of 13 samples out of 32. The VDMs, calculated from the measured palaeointensities and the inclinations, show the splitted distribution around the mean VDMs in the previous reports. This implies the geodynamo intensities may have more complicated distribution than those previously suggested by the palaeomagnetists. The relative intensity change in the nondipople/dipole fields was investigated using the direcions of the sedimentary records of the Matuyama-Brunhes transition. The records were obtained from the Boso marine sediments in Japan. The spectral analyzes suggest that the short-period variations, probably of the order of 10^2 years, are remarkable in the transition field.