AVOIDING STRATIGRAPHIC CONFUSION IN EXPLORATION: THE NEED FOR STANDARDS IN SEQUENCE STRATIGRAPHY

Abstract

As interpretations of sequence stratigraphy are published in increasing numbers in the petroleum exploration literature, the potential for confusion also increases because there are no rules for the classification or naming of the identified sequences. At present it is difficult to apply databases and geographic information systems to sequence stratigraphy, particularly when organisations with different outlooks and approaches attempt to collaborate and merge their databases.

Despite sequence stratigraphic concepts having been in the literature for over two decades, no scheme for standardisation has achieved consensus in the geoscientific community, either within Australia or internationally. Three areas in particular need to be agreed on: (1) how sequence units should be defined; (2) the hierarchy of those units, and on what basis; and (3) a standard scheme for naming units.

The two basic ways of subdividing a succession into sequence units, the Vail–Exxon and Galloway methods, both rely on the enclosing boundaries being defined first. Various hierarchies of units have been proposed, in which there is often a clear desire to link the scale of sequence units to phases of geological evolution or stratal boundaries of different orders. In addition, most workers use informal names, but formal names are becoming more common. Consequently, it is essential that workable national guidelines be developed to ensure that communication and computer compatibility are not impeded.