This page is meant to provide a snapshot of my current research directions. It is not an exhaustive list of all of my ongoing projects and interests! As mentioned before, there are two main research directions in the DRG - tectonic inheritance and strain analysis, specifically penetrative strain. I've recently become interested in the distributed deformation around fault strands, and in the complex geology of Vietnam!
Tectonic Inheritance/Fracture Characterization
I am building on work from former students Jerlyn and Tatiana, who created lineament maps of the SE Nebraska/NE Kansas region, and started to map fractures in the field. The goal of this project is to assess the relationships between present-day fracture networks and the locations and orientations of known faults in the Midcontinent Rift/Nemaha Uplift region. There is now a published paper on the fracture networks, and I have previously published restored cross-sections across both structures. This work suggested that there has been reactivation on both the Nemaha Uplift and Midcontinent Rift during the Laramide orogeny, previously not thought to affect structures in the interior of the continent. However, the presence of strong fracture networks in the Cretaceous units, subtly different from the networks in the Permian and Pennsylvanian units, strongly indicates tectonic activity post-early Cretaceous.
Penetrative Strain - Magnitude and Distribution
This is an ongoing project, aiming to provide a theoretical framework for evaluating the penetrative strain component of deformation at any point in an orogen. Penetrative strain is the strain accomodated on a sub-cross-section (that is, grain or outcrop) scale - not taken up by major thrusts or folds. So far, we have created models in brittle and ductile-based systems (both papers published in Lithosphere) with work in progress on systems with multiple detachments. The models provided a theoretical framework for penetrative strain distribution and magnitude in a fold-thrust belt. Ongoing work also aims to link outcrop-scale penetrative strain with the analog models, and to assess the penetrative strain component in a basement-involved uplift. Field areas for this effort are the Rattlesnake Anticline and Bighorn Mountains, WY, and the Front Range, CO.
Distributed deformation around fault strands
I have recently been able to access core from the Nankai Accretionary Prism, close to the megathrust that ruptured in the 11 March 2011 magnitude-9.0 Tohoku-Oki earthquake. Core from other megathrust zones is also being sought, typically through IODP channels. The goal of this research is to determine how deformation is accomodated in a fault zone, away from the major slip features, and to identify whether that correlates with clay content or other mineralogical factors as well as distance from the main slip surface. The results will provide information on strain partitioning between slip surface and surrounding rock, and may provide insight into why some megathrusts are "locked" and some produce huge earthquakes with large amounts of aseismic slip.