Abstract: Regional Seismic Interpretation Using Sequences and Eustatic Cycles

R. M. Mitchum, Jr., P. R. Vail, R. G. Todd, J. B. Sangree

Seismic sequences provide fundamental mapping units for a regional stratigraphic framework. Their use allows prediction of generalized age and depositional characteristics by recognition of worldwide eustatic control on sequence deposition, superposed on regional tectonic and lithologic control.

A sequence is a stratigraphic unit bounded by unconformities or their correlative conformities at its top and base. Sequences are ideal mapping units because (1) their boundaries are recognized readily and correlated seismically; (2) they are natural genetic depositional units deposited within a limited time interval defined by the ages of the sequence boundaries where they are conformities; and (3) major sequences are synchronous globally because of deposition during eustatic cycles.

Major applications of the sequence concept include the following: (a) construction of a regional stratigraphic framework within which to make facies, tectono-environmental, or paleogeographic studies; (b) analysis of seismic-cycle configuration within sequences for lithologic or environmental predictions; (c) recognition of cycles of eustatic changes of sea level; and (d) a potential system of global stratigraphy based on eustatic cycles.

An example illustrates a regional sequence framework, its relation to eustatic cycles of sea-level change, and generalized mapping of seismic facies and environments within the sequence framework.

AAPG Search and Discovery Article #90972©1976 AAPG-SEPM Annual Convention and Exhibition, New Orleans, LA