Simultaneous Decompaction and Restoration: An Improved Method for Basin Modeling

GEISER, JAMES, Geo-Logic Systems, Inc., Boulder, CO, ROBERT RATLIFF and ROY KLIGFIELD, Geo-Logic Systems, Inc., Boulder, CO, and University of Colorado, Boulder, CO, and ALAN MORRIS, Geo-Logic Systems, Inc., Boulder, CO, and University of Texas, San Antonio, TX

Palinspastically restored cross sections allow examination of the geological history of structurally complex basins. Decompaction corrects the restored section geometry for the effects of material deposited since deposition of the restoration horizon. Restored stratigraphic thicknesses depend on original thicknesses, present-day and restored burial depths, and knowledge of porosity variation with depth. Traditional decompaction methods consider only the change in vertical position; however, restoration of contractional and extensional faulting also requires the horizontal translation of material points. Because the decompacted thickness of a given unit depends on the material above it in both the present-day and restored states, the horizontal translation of hangingwall points can sig ificantly affect footwall decompaction. We have designed a new decompaction method in which points in the restored state retain knowledge of their locations in the present-day state. This permits present-day and restored burial depths and unit thicknesses to be determined in areas with relative lateral movement between material points, i.e., areas where faulting contributed to basin development. Application of the method to sections in the Gulf of Mexico and the North Sea demonstrate its utility in generating more accurate interpretations of basin history.

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)