笔者研究了内蒙古索伦地区中二叠统哲斯组泥质岩石中有机质的激光拉曼光谱特征,并探讨了拉曼光谱参数对有机质热演化程度的表征。研究区样品D1谱带吸收峰平均值位于1350.55cm-1附近,G谱带吸收峰平均值位于1602.55cm—1附近,G谱带与D1谱带的位置差变化于252.00±;G谱带与D1谱带的面积比集中在0.52附近,表明有机质经历的热演化温度约为250°C。应用拉曼光谱地质温度计估算了有机质的热演化温度,其平均温度为265°C;采用镜质体反射率地质温度计估算的有机质热演化平均温度为273°C,两者吻合。综合分析部分估算温度偏高的原因,结合无机矿物的成因标志,揭示研究区中二叠统哲斯组地层经历的极低级变质温度可能<250°C。
The authors study the laser R a m a n spectrum characteristics of organic materials in pelitic rocks in Middle Permian Zhesi Formation from Suolun area, Inner Mongolia and discuss the indication of R a m a n spectrum parameters on thermal evolution degree of organic materials. The spectra show an average “D1 ban d” peak at about 1 350. 55 c m -1 and an average “G b an d” peak close to 1 062. 55 c m -1. Distance between these two peaks is around 252. 00 ± ,with area ratio of “G ban d” to “ D1 b and” around 0? 5 2 ,which indicate that thermal evolution temperature of organic materials is about 250 °C . The average thermal evolution temperature of organic materials estimated by the R a m a n spectra geothermometer is 265 °C , consistent with that estimated by the vitrinite reflectance geothermometer (273 〇C ) . Factors that caused part of the relatively high estimated temperatures are comprehensively examined. Combining the genesis mark of inorganic minerals, the authors suggest that the very low-grade metamorphic temperature that Zhesi Formation experienced in Suolun area is likely < 250 ° C .