Integrated Quantitative Stratigraphy off Northwestern Australia Using Fossil, Seismic, and Petrophysical Data

C. M. Griffiths, P. Baumgartner, R. Buffler, X. Golovchenko, F. M. Gradstein, M. Kaminski, U. Von Rad, M. Schott, P. Williamson, T. Wonders

A combined analysis of seismic, biostratigraphic, and petrophysical data from the Argo Abyssal Plain and Exmouth Plateau sites drilled during ODP Legs 122 and 123 illustrates the potential of modern computer algorithms to complement traditional stratigraphic analysis techniques. The algorithms used include deterministic and probabilistic ranking and scaling using the Stratcor method, which allows integration of a wide variety of stratigraphic data in a single composite section. The composite results were rescaled in linear time and, for each well, were subjected to burial and subsidence analysis. Restored thicknesses prior to burial were estimated for each lithology from the porosity/depth function at each site. Three major phases of subsidence occur in the Triassic (rift phase), Late Jurassic to Early Cretaceous, and middle Cretaceous. The latest two phases relate to ocean opening first in the region of the Argo Abyssal Plain, followed by the Gascoygne Abyssal Plain.

Additional correlation assistance is provided by the use of genetyping algorithms applied to both petrophysical and biostratigraphic data. Syntactic pattern recognition was used to relate log sequence breaks to the seismic sequence analysis. The results of the quantitative stratigraphic correlations will be discussed in relation to the regional stratigraphy.

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