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

第一年就开发出了实验仪器并用于测试样品的测量。交变场消磁器的最大输出为 120mT，场增减速率恒定。该恒定性为 100mT/60sec，因为较高的速率往往会导致较小的 ARM。ARM 与进行比较的 NRM 或 TRM 并行获取。这样的 ARM 可以针对各向异性效应校正 NRM 或 TRM 强度。最高温度加热时间为10min。和20分钟。分别在第一次和第二次加热中。样品采集自大山火山（日本）、安第斯火山地区（秘鲁）和大同单生火山（中国）。它们都是在布鲁尼时代形成的。 Shaw 方法的双重加热导致 32 个样本中有 13 个成功。根据测量的古强度和倾角计算出的 VDM，显示了先前报告中平均 VDM 周围的分裂分布。这意味着地动力强度的分布可能比古地磁学家之前提出的更为复杂。使用松山-布伦赫斯转变沉积记录的方向研究了非偶极子/偶极子场的相对强度变化。这些记录是从日本房总海洋沉积物中获得的。光谱分析表明，过渡场中的短周期变化（可能约为 10^2 年）非常显着。

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.