ABSTRACT: Kinematic Constraints on the Construction of Geologic Cross Sections: Examples from the Papuan Fold Belt, Papua New Guinea

MARSH, ANTONY J., DONALD A. RODGERS, and GARETH TAYLOR,* CogniSeis Development, Inc., Houston, TX and Singapore

Accurate construction of cross sections through potential hydrocarbon plays in areas of complex deformation requires that cross sections honor all available data and be kinematically viable. The Papuan fold belt, an important exploration play, has received considerable attention in the literature. We examine several regional cross sections based upon existing field, well, and geophysical data from Papua New Guinea that were carefully balanced by hand (Hill, 1991, AAPG Bulletin, v. 75, p. 857-872) using line length and area balancing techniques. Restoration of Hill's original interpretations using the additional constraint of flexural-slip deformation finds several areas that are kinematically inadmissable. After modifying the restored sections, we produce a series of kinematically and geologically admissible cross sections by transferring the modified restorations back into the deformed state.

The modeling is accomplished using GEOSEC, a program for cross section construction and balancing. The resulting deformed state sections are different in prospect-scale detail from Hill's sections. These results illustrate the conclusion that cross sections can be balanced by area and bed length and still be kinematically incorrect. The use of kinematics in the construction of geologic cross sections

provides an additional constraint which can improve structural interpretations in areas of complex geology.

AAPG Search and Discovery Article #91015©1992 AAPG International Conference, Sydney, N.S.W., Australia, August 2-5, 1992 (2009)