The continued demand for higher stratigraphic resolution has resulted in the development of several quantitative stratigraphic methods, such as Ranking & Scaling, Unitary Association and Graphic Correlation. We consider Graphic Correlation as a component of a numeric stratigraphy approach, aimed at easy communication of stratigraphic data in multi-disciplinary projects.
Graphic Correlation is a quantitative, but non-statistical technique to determine the coeval relationships between two sections by comparing the ranges of taxa in both sections. One of these is a designated Standard Reference Section. Graphic correlation compares the rate of sediment accumulation in one section with that of the other and thus enables (and forces) a stratigrapher to consider the sedimentological events along with the biostratigraphic events.
By repeating this process for many sections a Composite Standard section can be built, which shows the maximum ranges of species and the precise succession of their tops and bases. The process can be applied to block or regional studies, and extended to global standard schemes.
Once a Composite Standard Section is established for an area, age measurements of beds (or reliable ages of marker species) can be graphed in, which converts the Composite Section to a time scale.
The practical use of Graphic Correlation with a time converted Composite Standard Section is the recognition and measurement of hiatuses, which can be of great geological and economic importance. It also provides an estimate of the subsidence rates in an area, both of which are essential data input for Geohistory Analysis or other basin modelling packages.
Gradstein, F.M., Agterberg, F.P., Brower, J.C. & Schwarzacher, W.S., 1985. Quantitative stratigraphy. D. Reidel Publishing Co., Dordrecht, Holland. 598 p.
Hood, K.C., 1986. GraphCor: Interactive Graphic Correlation for Microcomputers V.2.2. Published by K.C.Hood
Shaw, A.B.m 1964. Time in stratigraphy. McGraw-Hill, New York, 365p.
Neal, J.E., Stein, J.A. & Gamber, J.H., 1994. Graphic Correlation and sequence stratigraphy of the Paleogene of NW Europe. Journal of Micropalaeontology , 13: 55-80.
Scott, R.W., Franks, P.C., Stein, J.A., Bergen, J.A. & Evetts, M.J., 1994. Graphic correlation tests the synchronous Mid-Cretaceous depositional cycles: Western Interior and Gulf Coast. In: Rocky Mountain Association of Geologists. Unconformity related Hydrocarbons in Sedimentary Sequences. Denver, Colorado, 89-98.
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