Recently, scientists have proposed that plate tectonic processes may be strongly influenced by erosion. This implies that processes acting over the surface of the Earth may be coupled to those acting within its interior. This project will use analogue models to study the influence that erosion may have played on the kinematic development of the Precordillera fold-and-thrust belt of central Argentina. Here, extensive field data constrain the kinematics of the fold-and-thrust belt, and work farther south in the Cordillera Principal, Cordillera Frontal, and Precordillera indicates that erosion may exert an important control on the evolving geometry of the fold-and-thrust. This project uses analytical formulations and scaled sandbox analogue models to understand how the kinematics of the fold-and-thrust belt evolve under different erosional conditions. An orogen-scale erosion rule that relates erosion rates to intrinsic factors, such as lithologic differences in rock erodibility, and extrinsic factors, such as climate changes will be used. These results will be compared to the observed kinematics of the fold-and-thrust belt to deduce the role that erosion played in the mountain belt''s development. In addition, a series of forward analogue models that consider temporal changes in erosional conditions associated with the exposure of rock types with varying resistance to erosion and long-time-period changes in climate will be performed. This multi-tiered approach will first provide insight into those aspects of the kinematics of the Precordillera fold-and-thrust belt that may be strongly influenced by erosion, and then will expand these specific results to a range of changing erosional conditions that might be related to exposure of different rock types in fold-and-thrust belts and global climate changes.
The discovery that deep earth processes may be linked to those of the shallow earth is perhaps one of the most important recent contributions to the theory of plate tectonics. If true, this concept will temper interpretations of the past and current operation of mountain belts, and may lead geoscientists to reinterpret many aspects of the geologic record in new ways. Currently, most studies that seek to establish this new paradigm have concentrated their efforts on qualitative comparisons of general numerical model results with scare field observations. This study will be the first to compare specific model predictions to a well-studied mountain belt to determine if surface processes are necessary to explain its development. Results of this research will help to establish this linkage between deep earth and surface processes, and to understand how strong these links may be in different tectonic and erosional environments. The study includes an international team of scientists from the United States, Venezuela, and Canada, and will promote the education of under-represented high school students through outreach programs.
