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Identification of the volcanic quartz origins from dune sand using a single-grain RTL measurement

2004; Elsevier BV; Volume: 23; Issue: 9-10 Linguagem: Inglês

10.1016/j.quascirev.2003.09.010

1873-457X

T. Yawata, Tetsuo Hashimoto,

Indoor Air Quality and Microbial Exposure

In an earlier study, we found that quartz grains extracted from Niigata dune sand all contained red thermoluminescence (RTL) phenomena. This RTL could subsequently be attributed to the volcanic origin of the material. The Agano River is assumed to be the main source of the Niigata dune material. Using the single aliquot regenerative method, which involves the measurement of several hundreds of grains, the measured equivalent doses from the RTL-quartz grains were larger than expected. Consequently, a single-grain method combined with RTL-measurement was developed to determine the equivalent doses from each quartz grain. Placing a biotite plate with a central hole for the sample grain on the sample disk made a significant contribution to keeping background levels as low as possible. The histogram of the equivalent doses evaluated from 72 quartz grains revealed that the Niigata dune originates from at least four different volcanic sources around Agano River. One of them is the Numazawa volcano, because the minimum equivalent dose values from the single grain method are equal to those of quartz grains from the Numazawa pumice.