STAGES IN THE ALTERATION OF SEDIMENTARY ROCKS AND PARAGENETIC RELATIONS OF COMBUSTIBLE MINERALS

Alterations of coal organic matter in the course of metamorphism are considered in the paper. Under the influence of temperature and pressure the organic matter contained in sedimentary rocks is liable to easier and quicker alteration than the inorganic substance. As a result of a study of oil- and coal-bearing sediments it is suggested that the transformation of the organic matter contained in coal disseminations should be used as an indicator of general sedimentary rock alterations, taking place during their submergence into higher temperatures and pressure zones. The reflectivity of vitrinite, determined by means of photocells under the microscope serves as a quantitative expression of different sedimentary rock transformation stages. Thus, 22 stages of sedimentary rock alteration have been isolated. These stages have been subdivided into 6 subgroups and 3 groups. Paragenetic relations between coal alterations and oil distribution in sedimentary rocks of different stages have been established.—Auth. English Summary.