HIGUERA-DIAZ, IVAN C., Northern Illinois University, Department of Geology and Environmental Geosciences, DeKalb, IL
ABSTRACT: 3-D Geometry and Kinematics of the Nuncios Detachment Fold Complex in the Sierra Madre Oriental, Monterrey Salient, Mexico
Fault
-related folds are significant hydrocarbon traps in many geologic
settings throughout the world. Because of this and an increasing use of
fault
-related
folds in seismic risk assessment, the past twenty years has witnessed an explosion of
research into the
fault
-related folding process. Though commonly limited to 2-D plane
strain environments, these studies have dramatically improved our understanding of such
things as folding rates,
fault
geometry,
fault
-slip rates, fold-related strain, and the
competition between hinge migration and limb rotation.
However, significant gaps remain in our understanding of the 3-D fault
-related folding
process. In folds with curvilinear axes or plunges exceeding ~ 20 degrees, substantial
out-of-plane material transport can occur. Existing models cannot account for this type of
deformation and a precise field characterization of these 3-D motions has never been
published. This study aims to produce such a characterization by studying mesostructures
and thickness variations throughout the plunging nose of a map-scale detachment fold in
the Sierra Madre Oriental of northeast Mexico. The hypothesis is that in a fold exposed
over a large geographic area with high topographic relief, preserved mesostructures and
stratigraphic thickness variations will constrain the true 3-D fold kinematics.
The development of this 3-D model of deformation will permit the restoration to the real position of data that have been taken in folded structures.
AAPG Search and Discovery Article #90909©2000 AAPG Foundation Grants-in-Aid