NAIL, ROBERT S.
PGS Reservoir, Houston, TX

Abstract: Correlation of the Exxon/Haq, Shell/GCSSEPM, and PaleoData Sequence Stratigraphic Charts

The Exxon/Haq (E/H), Shell/GCSSEPM (S/G), and PaleoData (PD) sequence stratigraphic charts are correlated over the Pliocene-Pleistocene interval (1.00 Ma-3.79 Ma). Correlation of these three models demonstrates some of the more common problems associated with identifying and defining sequences Within a given time interval the number of sequences identified by each model can vary significantly. From Late Pliocene (approx. 4 Ma) to the present, E/H model interprets 5 sequences, S/G interprets 10 sequences, and P-D interprets 14 sequences. All three models use similar biostratigraphic events, but the interpretation of these events varies. Most of the sequence elements defined by the E/H model use biostratigraphic zones, which are not considered high-resolution biostratigraphic data. Alternatively, the S/G and P-D models use high-resolution paleodatums to define most of their sequence elements.

Between the S/G and P-D models there are five common horizons, each defined by like bio-events and interpreted as a maximum flooding surface. Using these horizons as direct correlation lines, intervening biostratigraphic data and interpreted sequences are compared. Results suggest some sequences can be directly correlated (e.g., S/G sequences 3.7B and 3.7C are equivalent to PD sequences 2.8 and 2.5, respectively). However, the majority of the sequences cannot be directly correlated, due to differing interpretations related to the defined paleo-datum succession (LAD's of Globorotalia margaritae and Reticulofenestra pseudoumbilica) and interpreted significance of observed bioevents (e.g., S/G interprets the LAD of Calcidiscus macintyrei as defining the lowstand systems tract of sequence 3.9A, while P-D interprets this bio-event as defining the maximum flooding surface of their sequence 1.9).

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas