我国某些地区的海绿石特征及其对相环境分析的意义

海绿石矿物一般是在正常盐度的浅海环境中生成,可作为良好的指相矿物。在无化石的地层中海绿石可用来测定同位素年龄、进行地层对比和解释地层间断。此外,海绿石也可作为储油层沉积环境的综合指标之一。 本文通过各种方法对我国某些地区砂岩类型的自生海绿石的矿物学特征作了综合系统的研究。试图通过从已知到未知、从现代到古代作对比,对松辽盆地的某些储油层段相环境的确定,提出必要的实际资料,进而来讨论它们的沉积环境。

CHARACTERISTICS OF GLAUCONITES FROM SOME REGIONS AND THEIR SIGNIFICANCE IN ANALYZING THE FACIES ENVIRONMENT

This work mainly deals with the glauconites mineralogy collected from the finegrained feldspar-sandstone of Cretaceous Yaojiazu Formation and of the Shasan member of Shahejie Formation in Songliao basin.According to the external shape, the glauconites of several regions may be classified as follows: 1. spherulitic, 2. irregular granular, 3. pseudomorphs after other minerals, 4. irregular cement-like, 5. chamber colloid form and tongue-like. Moreover, the surface features of grains and character of grain-size have also been examined, The internal microstructures of the crystals can be distinguished into two classes, micro-crystalline, fine-flaky and radioted microcrystalline. It seems that the glauconites here investigated were mainly a sort of embryonic crystals or microcrystalline aggregates.The variations in color, the type of crystal structure, the chemical composition, as well as the condition of formation of the investigated glauconite were also discussed. In general, glauconites are formed under a condition from weak oxidation to weak reduction in a medium of slight alkaline to meta-alkaline.