The Age measurement of the tephra layers, fill in the San in district since the middle Pleistocene. Using the Thermo luminescence technique

本文首先研究了不同条件下热释光辐射电荷的积累速率。结果表明，在10 cm厚的铅盒中没有发生辐射电荷的积累。黄铜管或铜管中没有出现额外的辐射电荷。结果表明，埋在地下的热释光元件的辐射电荷在不同的区域是不同的。因此，辐射电荷率的测定必须在火山灰取样的同一点进行。作者在山阴地区对火山灰层的火山玻璃折射率、矿物成分等进行了测定，并以北陆地区的火山灰样品作为参考。并对这些火山灰的热释光强度进行了测量。据透露，这项技术是能够适用于所有这些火山灰。但由于矿物组成的原因，某些火山灰中辐射电荷的积累很少。例如，K-Tz，其中包含大量的石英颗粒，具有大量的辐射电荷积累。另一方面，Oginsen地区火山碎屑岩的热释光强度较弱，它们的地层年龄比K-Tz老。与K-Tz相比，北陆较古老的火山碎屑流沉积物的热释光相当强。戴森沉降浮岩的热释光强度有明显的差异。火山碎屑的热释光强度可以推算其沉降年龄。

At first, the accumulation rate of radiation charge of thermoluminescence in several conditions are studied in this research. As the results, accumulation of radiation charge weren't occur in the lead box of the thickness 10cm. The additional radiation charge in the brass or copper tubes did not occur. It is revealed that the radiation charge of the thermoluminescence elements laid under the ground were different at each region. So, it is clear that the radiation charge rate must be measured at the same point where tephra were sampled.In San'in district, the author examined the tephra layers as to refractive index of volcanic glass, mineral composition and a so on. And as a reference, some samples of tephra distributed in Hokuriku district were examined. And also, the thermoluminescence intensity of these tephra were measured. It is revealed that this technique is able to apply for all of these tephra. However, the radiation charge accumulation is a very few in some tephra because of their mineral composition. For example, K-Tz, which contains large quantities of quartz particle, has large radiation charge accumulation. On the other hand, the tephra of Oginsen area, which are older than K-Tz as to stratigraphically, their thermoluminescence intensity are weak. And the thermoluminescence of the quite older pyroclastic flow deposits of Hokuriku is quite strong in comparison with the K-Tz. Daisen fallout pumices have a clear deference thermoluminescence intensity each other. The thermoluminescence intensity of tephra can be calculated into their fallout age.