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Research by the Structural Geology Research Group has been supported by National Science Foundation Award #1220235 and by National Science Foundation Award #1659322 (through the Keck Geology Consortium). The text below summaizes these projects. To learn more about our work, please explore the links on the left sidebar or contact us directly.
Coupled fold-fracture evolution of the Stillwell anticline, west Texas (NSF Award 1220235)
Understanding the kinematic and dynamic links between fold and fracture formation is critical for the evaluation of subsurface fluid flow rates and pathways. The proposed investigation of a well-exposed fault-cored anticline will provide new data to improve our understanding of the links between mechanical stratigraphy, structural position, and fracture formation during the development of a fold system. The well-documented variation of exposed fold amplitudes and geometries of bedding within the Stillwell anticline system provides a unique opportunity to directly document the sequential development of fracture networks during contractional deformation and fold evolution. Field and remote-sensing methods will be integrated with the development of a detailed mechanical stratigraphy, new techniques of fracture intensity analysis, microstructural analysis of oriented thin sections, and computer kinematic modeling of fault-related fold formation to provide a new and detailed view of the way that permeability evolves during fold formation in carbonate systems.
The proposed investigation will aid in the development a sequential model of fault-cored folding and fracture development within the well-defined Stillwell anticline system. Reconnaissance field investigation of the anticline system has revealed fold geometries apparently tied to different stages of fold evolution, so this work should lead to the development of a well-constrained new model of sequential fracture development within a carbonate stratigraphy that can be applied to coupled fault-fold systems worldwide. The distribution of strain at different stages of fold evolution will be tested using kinematic numerical modeling, with results that can be compared to the direct measurement of fracture intensities and other deformation mechanisms from different structural positions within the Stillwell anticline. Within this context, this investigation should reveal the dynamic link between fault propagation and changes in permeability anisotropy during folding of the overlying carbonate stratigraphy. The lithologic controls on the formation and evolution of faults, fractures, and folds will continue to be an important area of research because of the inherent importance of these features to the movement of fluids in the subsurface.
The proposed investigation will strengthen the Geosciences program at Trinity University and will impact undergraduate students at all levels. The proposed research will integrate field instruction with field research, ensuring that undergraduate researchers gain a thorough overall understanding of fundamental geological processes and three-dimensional relationships in the context of their own work. As part of their research, students may also have the opportunity to travel to a research lab to perform analyses with faculty at another institution, thus gaining both research experience and a chance to interact with researchers outside of Trinity University. All research results and subsequent products will be made accessible to all Trinity students and to the general public through a collaborative dissemination project with the Trinity University library. Research results will also be made available to other educational institutions that visit and work in the Black Gap Wildlife Management Area, an effort facilitated by Mike Pittman, a biologist and project leader with the Texas Parks and Wildlife Department. Undergraduate students impacted by the proposed project will likely include those from under-represented groups, including women and Hispanic students, which are well-represented at Trinity University. Finally, the project will aid in the professional and scientific development of the PI, a junior faculty member.
Structural evolution of a segmented normal fault transfer zone, Sevier fault, southern Utah (NSF Award 1659322 through the Keck Geology Consortium)
While it has long been recognized that major normal fault systems are commonly segmented in map view, as opposed to continuous, planar surfaces, only recently have researchers made significant advances in the role that segmentation plays in the evolution of these fault systems. The geometry and relative strength of links between fault segments can strongly influence the propagation of slip during an earthquake, and the perturbations of the local stress field caused by interaction of fault segments can influence the formation of relay ramps, minor faults, and associated fracture networks in transfer zones between synthetic normal fault segments. We investigate the evolution of a significant transfer zone along the Sevier fault zone, Utah, in order to document the evolution of brittle deformation features across a range of scales. Our findings have implications for groundwater flow, hydrocarbon migration, and ore mineralization.