Thermoluminescence of limestones, calcites and other minerals (1 st. report)

Abstract

As a preliminary survey, about 127 specimens of limestone from Ohazama-Miyamori District, Iwate Prefecture were checked visually for natural thermoluminescence by observing their behavior when placed on a hot plate in dark room. It was found that about 70% of the limestones tested were thermoluminescent and that the colour of all the emitted light are orange yellow which continue for a short time.
In this report, some of the facts obtained by this preliminary study are mentioned. That is:
1. Thermoluminescence is appeared only by the first heating and never occured after that.
2. Thermoluminescence is seemed to have no relations to (a) the influences of granite intrusions, (b) chemical constituents of limestones, (c) grain size and colour of limestones.
3. X-ray radiations act as an activator for the thermoluminescence.
4. Ultra violet ray radiations do not act as an activator for the thermoluminescence.