Stratigraphic Correlation

comparison of layers of sedimentary and igneous rock of the same age and relating them to subdivisions on a single stratigraphic scale. The comparison may cover sections taken from different boreholes in single oil-bearing areas or sections from boreholes in separate deposits (coals, salts), as well as large areas and even several continents (telecorrelation and intercontinental correlation). Correlation uses all possible methods of comparison—logging data, tracing of marker beds and their particular layering, biostratigraphic methods, and isotope determinations of the age of rocks. As a result of correlation a stratigraphic chart is compiled. In the left part of the chart subdivisions of a single stratigraphic scale are drawn and, in the right part, a stratigraphic scheme of deposits encountered in the region being studied.