--> Abstract: Coupling 3D Numerical Modelling of Contractional Structures, Sedimentation and River Network Evolution: The Stratigraphic and Geomorphic Expressions of Fault-Related Fold; #90063 (2007)

Datapages, Inc.Print this page

Coupling 3D Numerical Modelling of Contractional Structures, Sedimentation and River Network Evolution: The Stratigraphic and Geomorphic Expressions of Fault-Related Fold

 

Bernal P, Asdrúbal J.1, Stuart Hardy2, Robert Gawthorpe3 (1) PDVSA-Intevep, Los Teques / Edo. Miranda, Venezuela (2) Universitat de Barcelona, 08028 Barcelona, Spain (3) Manchester University, Manchester, United Kingdom

 

Both drainage systems and syntectonic sedimentation responds to the interplay between stratigraphic and tectonic processes in three-dimensions. Current numerical techniques generally employ two-dimensional cross-sections or non-lateral propagating 3-D structures to investigate syntectonic sedimentation in contractional settings. In this study, the modelling of syntectonic sedimentation and river network evolution in three-dimensional contractional structures is achieved through use of a partial differential equation in a forward numerical approach. Structural deformation in the transport direction is described by fault-related folding and the rate of lateral growth is controlled by a scaling relationship between fault width and maximum displacement.

 

Modelling results highlight the differences between situations with lateral, including different fault scaling laws, and non-lateral fold growth and suggest these can be recognised by analysis of pre- and syn-tectonic strata and drainage network geometries. Furthermore, analysis of two-dimensional cross-sections can generally lead to equivocal and often erroneous interpretation of deformation style. Low sedimentation compared to tectonic rates and accommodation promotes offlap and onlap configurations as well as time transgressive unconformities. In high accommodation scenarios, growth triangles within syntectonic sediments do not arise. In addition, modelling suggests that natural structure form when: (1) the evolution of the fault is nonself- similar, or (2) the fault grows as a result of thrust faulting events with similar displacements along strike that are terminated abruptly at the fault tips. The numerical models compare well to outcrop and subsurface data from natural thrust systems and can be used as templates to aid interpretation of structural geometry and kinematic evolution.

 

AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California