Lithogenesis stage of Devonian sediments of middle Timan (Zil’ma river basin)

The article contains results of determining the stage of lithogenesis (catagenesis) of Devonian terrigenous sediments by degree of spores discoloration. This method is only possible because the whole coaled plant material in the sediments is exclusively represented by fusenite. In the Timan-Pechora province optical method of determining the level of organic material catagenesis first applied.