Abstract
The vitrinite reflectance is a geothermometer in diagenetic to low grade metamorphic rocks, and standardized in ISO, JIS and ASTM. However ordinal method can not be applied for small grains less than 75 μm. The criteria based on thermo-plasticity can recognize vitrinite in small particles. A new device with double illuminations of the Keller type for lighting wide area and the Critical type for lighting spot area was developed for spot analysis with wide field observations. This system enables to make thermal mapping along fault zone and estimation of paleo-temperature of fine-grained sediments. A part of this method and apparatus is registered as the patent 2007-132795 in Japan.
