Evaluating Fold And Thrust Systems Within An Inverted Basin: Indio Mounntains, West Texas

Fold and thrust belts often are complicated by out of sequence thrust faulting and inverted basins display these structures particularly often due to reactivation of original normal faults as well as complex topographic evolution. The Indio Mountains lie along the northern margin of the Chihuahua trough which formed as a mid-Cretaceous extensional basin and was subsequently shortened during the Laramide orogeny, making the Indio Mountains an exceptional site for studies of structures produced by large scale basin inversion. This study focuses on the subsurface structures in a complexly imbricated thrust window developed along the paleo rift basin margin. This study examines the area through a multi-method research approach that includes: a) new or improved definition of stratigraphic units/subunits within the Cretaceous Yucca formation; b) the production of a geologic map from surface rock exposures; c) the collection of geophysical data and processing; d) the construction of a 3D model of the area. Through this data the study characterized a fold-thrust system developed in an inverted system and evaluated the role of out of sequence thrust faults involved, correlated with geophysical modeling, and assessed models for thrust systems in these tectonic settings. There is worldwide demand for rational and thorough subsurface geologic models, particularly in inverted basins which are commonly major hydrocarbon producers. Recently 3D mapping programs have been employed to improve subsurface resolution but despite the demand the process is in its infancy (Russel et. al., 2013). The resulting 3D model greatly served as an improved digital elevation model (DEM). Gravity analysis resulted in small changes, yet nonetheless correlated well with surface geology and fault associations. Overall, the collective of data resulted in the geologic interpretation of an vi extremely shallow upper plate duplex, and ambiguous thrust sheet identification due to severe deformation in the area