Abstract
Thermal luminescence (TL), a phenomenon which can be seen in such minerals as feldspar and silica, is applied to investigation of the origin of the clay layers (loess deposits) that cover a vast surface of the Japanese landform. In utilizing these deposits, we have also attempted to do TL-dating by employing the TL photomultiplier. The first attempt is to distinguish between loess and tephra deposits on the basis of TL color image analysis (TLCI-CIA). After X-ray irradiation, the TL photographs of quartz particles can be separated into the deposits shown by red and blue colors, respectively, on the CIE chromaticity diagram. This result indicates that TLCI-CIA is a useful method for investigating the origin of Pleistocene deposits.
Second, a dating experiment was carried out for loess deposits in the Kamikita Plain, Aomori Prefecture. The blue-TL photon count numbers of fine particles less than 63μm in diameter are increasing in descending order on the columnar section. The blue-TL ages estimated by the Toya tephra (110ka) indicates dates raging from 47ka to 308ka. This basic experimental result indicates the possibility of using TL-dating for Pleistocene age determination.
