New method for quantification of clastic sedimentary sequences in time series analysis

Parameters related to the lithology of a clastic sequence may be used for its quantification. Settling velocity of constituent grains of a bed, which is one such parameter, has been taken as a basis for the numerical characterization of clastic rocks and the construction of a stratigraphic time-series representing the sequence. In order to account for varying bed thickness, one may divide an entire section into subsections of equal thickness, varying from 0.1 to 1.0 m. depending on the problem and the nature of data. For each subsection the proportions of thickness of different constituent clastic beds then are multiplied by modified settling velocity values corresponding to their respective grain size characteristics. The resulting numbers are added for each subsection to form the depth series to be analyzed. The proposed method is explained with the help of a case study based on three sections of clastic sequences obtained from the Gondwana coal fields in India. The depth series constructed from the sections have been analyzed by time-series methods. Results of the analysis have been used to demonstrate the applicability of the method in stratigraphic correlation.