Fault Propagation Folding on the Central Basin Platform, West Texas

Blumentritt, Charles H.¹, Kurt J. Marfurt¹, Michael Murphy¹ (1) University of Houston, Houston, TX

We use 3-D seismic data to define the three dimensional geometry of a fault block in the Central Basin Platform, west Texas. The fault block lies east of the Fort Stockton uplift and is bounded by two north-striking basement involved high angle reverse faults and limited to the north and south by a tear fault and a monocline. Deformation associated with the basement faults is characterized by faulted strata at deep structural levels and related folding at shallow levels. Asymmetric fold geometries indicate the reverse faults are east-directed and root deeply into Precambrian crystalline basement. No evidence of significant strike-slip faulting was found along basement reverse faults. Along strike to the south, the fold-fault system forms a monocline, while to the north it merges with an east-west striking tear fault that shows left-lateral oblique slip of offset stratigraphic horizons and small-scale structures. Lineaments determined from volumetric curvature data indicate counter-clockwise, vertical axis rotation of the basement fault block.

2-D forward models of our structural interpretation were constructed to assess the geometry and kinematics of deformation. Our results show that deformation can be explained by a fault-propagation folding model that incorporates trishear theory; both the geometry and magnitude of displacement along basement-involved faults varies along strike; and the magnitude of slip along basement reverse faults broadly correlates with that along basement tear faults suggesting the two are linked.