ABSTRACT: Graphic Correlation and Sequence Resolution

David D. Reimers

Graphic correlation consists of using a two-axis graph to express the time equivalence between two stratigraphic sections. The points of exact equivalency plotted on this graph form the line of correlation. All paleontologic datum levels that are time equivalent in the two stratigraphic sections will lie on this line. The shape of the line depends on relative rates of sedimentation or the presence of hiatuses in the two sections.

This method of correlation has been tested in hypothetical cases and in outcrop and Deep Sea Drilling Project sections. In all cases the solution to the correlation of the sampled sections has been greatly aided or resolved through the use of graphic correlation.

The application of this method to the correlation of wells drilled by the petroleum industry and to the identification of condensed sections in the stratigraphic sequences is presented here. The method used for the well correlation and condensed-section determination used nannofossil extinction data and maximum total abundance levels as the coordinate points plotted in the graphs. The resulting graphs provide a basis for confirmation of the correlations and assurance of the correct identification of the condensed sections in the sampled stratigraphic section.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990