Lithologic-facies analysis of coal-bearing sediments and its importance for the solution of practical tasks of the coal geology In Iran

Lithologic-facies analysis of coal-bearing sediments and its importance for the solution of practical tasks of the coal geology In Iran.      Lithologic-facies analysis of coal-bearing sediments and its importance for the solution of practical tasks of the coal geology In Iran

The lithologic-facies analysis method was elaborated and for the first time applied widely to coal-bearing sediments in the USSR. During the last two decades this analysis became a constituent part of the researches carried out by Soviet geologists in the Donetsk, Kuznetsk, Pechora, Karaganda and other coal basins of the country (Zhemchuzhnikov et a1., 1959; lvanov, 1967; Timofeev, 1969 and others). The application on the lithologic-facies analysis method allowed researchers to pass from observing purely outer connections of natures phenomena to mastering their Inner essence. In other words, a descrip­tive approach to studies of coal-bearing sediments was replaced by an approach which made   it possible to reveal the genetic essence of the geological proces­ses participating in the terming of coal-bearing series. As a result, the li­thologic-facies analysis method raised considerably the trustworthiness of stratification, correlation and prediction of coal presence in productive sediments

The essence of the method under discussion consists in determining the fa­cies nature of layers and beds of sedimentary rocks on the basis of lithologic indications ascertained visually and microscopically. The most important of them are: granulometric composition, bedding, fauna, flora, inclusions, coloration, petrographic composition, character of contacts. Among all these indications stand out primary ones, I. e. those which are inherent in the sediment and unco­ver its genetic nature, and secondary indications which appear in the sediment in the process of its turning to the rock. The primary genetic indications serve to reconstruct the sedimentation medium which forms the basis for the concept “facies”. Thus, a fossil facies is a layer or a bed of sedimentary rock with a certain set of lithological indications

areas occupied by a facies, etc

The data on the facies belonging of rocks approbated in this way is extended subsequently to the whole sequence of the sedimentary series; for this Purpose atlases of facies and lithologic types of rocks are usually used. In the Soviet union, similar atlases were compiled for the majority of coal basins (Atlas of lithogenetic types, 1956; Botvinkina, 1962: Timofeev, 1969 and others)