Geochronological Models Based on Quantitative Signal Processing of Chemical Stratigraphic Data

Douglas F. Williams, Dwight M. Trainor, Ian Lerche

Chemical stratigraphy is becoming an increasingly important tool in chronostratigraphic interpretations of exploration wells. Chemical stratigraphy data are well suited to modeling in the time and frequency domains with quantitative signal processing and data-dependent filtering techniques, such as power spectral analysis, autocorrelation, cross-correlation, cross power spectral analysis, phase-sensitive detection, and matched filters. Properly analyzed quantitatively, chemical stratigraphy data provide an ideal framework for stratigraphic correlation of thick sedimentary sections with a high degree of resolution, chronostratigraphic interpretations with a high degree of reliability, as well as mapping and timing of diagenetic trends and gradients.

In this presentation, we use a combination of these techniques to compare several recently developed types of chemical stratigraphies. One type record is based on global changes in the stable isotopic composition of seawater. The other type records are based on composite stable isotope and geochemical records for Pliocene-Pleistocene exploration wells from the northwestern Gulf of Mexico. Coherency analysis was used to subtract the global portion of the signal from the Gulf sections due to freshwater discharge vents, paleotemperature changes, diagenesis, and hydrocarbon migration.

AAPG Search and Discovery Article #91022©1989 AAPG Annual Convention, April 23-26, 1989, San Antonio, Texas.