Quantitative measurement of "Thermal Alteration Index" by means of computer graphics and its application to sedimentary basin analysis

“热蚀变指数”不被认为是一个定量指标，而被认为是一个定性指标，其可信度不如镜质组反射率。在本研究中，我尝试用“热蚀变指数”作为有机质亮度的数值。利用配备有4198图像指令程序的Olympus图像分析仪，对300余份泥岩样品中的花粉、孢子化石和无定形干酪根的亮度进行了测量。松属和杉木属花粉和块状无定形干酪根的亮度值与镜质组反射率（Ro）呈可逆相关。在埋藏成岩作用过程中，松属和杉木属的花粉亮度最常值发生不可逆变化。在厚第三系沉积的一个井眼和一个地表样带中，用松属和杉木属花粉最常见的亮度值确定的有机质成熟度，特别是强生油阈值与用镜质组反射率确定的值接近。结果表明，松木和杉木花粉亮度的最频繁值是有机质成熟或成岩作用的有用参数。在同一成熟期，松木和杉木花粉的亮度值分布较广。一个样品的50个松属和杉木属花粉粒的亮度最常值呈正态分布。因此，像镜质体反射率一样，对松木和杉木花粉粒的亮度最频繁值进行统计处理，解决了这一问题。

"Thermal Alteration Index" has not been recognized as a quantitative indicator, but as a qualitative indicator, and then it has not so much confidence as vitrinite reflectance. In this study I tried to indicate "Thermal Alteration Index" as numerical value of luminance of organic matter. Luminance of pollen and spore fossils, and amorphous kerogen isolated from about 300 mudstone samples, was measured by means of an Olympus image analyzer with image command 4198 program equipped a microscope.The most frequent values in luminance of pollen of Pinus and Tsuga and lumpy amorphous kerogen of a sample are reversibly correlative to vitrinite reflectance (Ro), respectivery. The most frequent values in luminance of pollen of Pinus and Tsuga irreversible change in the same way with burial diagenesis.In one borehole and one surface transect in whech thick Tertiary sediments deposited, organic maturation, especially the threshold of intense oil generation, determined with the most frequent values in luminance of pollen of Pinus and Tsuga in near equal to that determined with vitrinite reflectance. It is concluded that the most frequent value in luminance of pollen of Pinus and Tsuga is a useful parameter for organic maturation or diagenesis.The most frequent value in luminance of pollen of Pinus and Tsuga has a wide distribution at the same maturation stage. The most frequent values in luminance of 50 pollen grains of Pinus and Tsuga of a sample show a normal distribution. Therefore, this problem is solved, like vitrinite reflectance, with statistic treatment of the most frequent value in luminance of pollen grains of Pinus and Tsuga.