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

火山灰层的年龄测量，填入San in区中更新世以来。

• 批准号: 03680211
• 负责人: NOMURA Ryotaro
• 金额: $ 1.02万
• 依托单位: Kobe University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03680211/
• 关键词: thermoluminescence; Tephra; Tephrochronology; Daisen; Oginosen; 年代測定; 中、後期更新世; 山陰地方

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.

本研究首先研究了几种条件下热释光辐射电荷的累积率。结果，厚度为10cm的铅盒内没有发生辐射电荷的积累。黄铜或铜管中没有发生额外的辐射电荷。结果表明，埋在地下的热释光元件的辐射电荷在每个区域都不同。因此，很明显，辐射电荷率必须在火山灰取样的同一点进行测量。在山阴地区，作者对火山玻璃的折射率、矿物成分等火山灰层进行了检查。作为参考，对北陆地区分布的一些火山灰样本进行了检查。并且还测量了这些火山灰的热释光强度。据透露，这项技术能够适用于所有这些火山灰。然而，由于其矿物成分的原因，某些火山灰中的辐射电荷积累很少。例如，K-Tz含有大量的石英颗粒，具有大量的辐射电荷积累。另一方面，Oginsen地区的火山灰地层年龄比K-Tz更古老，其热释光强度较弱。与K-Tz相比，北陆地区较古老的火山碎屑流沉积物的热释光相当强。大仙沉降浮石彼此之间的热释光强度有明显差异。火山灰的热释光强度可以计算出它们的沉降年龄。