The development of out-of-sequence thrusts in mountain belts: Insights from physical models and image correlation.

Saad Haq, Purdue University

Analog models of thrust wedges in conjunction with analytical solutions have provided a robust framework to simulate and predict the progression of deformation in convergent Coulomb wedges. The inherent complexity of even the simplest modeling rheologies (e.g., variations in frictional behavior of sand) used to simulate deforming rocks in analog models can produce deformation that is a reasonable approximation for the complexity of the observed deformation in nature. The application of digital image correlation (DIC) methods has allowed us to precisely quantify the kinematics of these models, allowing for the high-resolution calculation of the evolving deformation fields. Utilizing both Eulerian and Lagrangian DIC methods has provided insights into both the instantaneous and long-term deformational response of frictional thrust wedges due to variations in mass flux (i.e., erosion, deposition, and accretion) and/or boundary conditions and has allowed us to examine deformation at a variety of time and length scales in developing wedges. The determination of where and when deformation is occurring, along with an understanding of modeling material properties allows us to develop a simple mechanical explanation to explain out-of-sequence deformation in frictional thrust wedges occurs.


Cutting edge research in structural geology geophysics geochemistry and tectonics