Development of New Techniques for Rock Deformation Using the Large Volume Torsion Apparatus

Washington University, Saint Louis MO

Investigators

Abstract

The field of rock deformation uses experimental devices to simulate the conditions in Earth’s interior by generating tremendous pressures, temperatures, and stresses. Deforming rocks in a laboratory setting allows researchers to control precisely the conditions that they impose, and test systematically the responses of rocks and minerals to these conditions. The data that are collected are used to better understand Earth’s structure, dynamics, and geologic hazards. For example, using rock deformation experiments scientists can determine the viscosity of rocks in Earth’s interior. These data, in turn, help us to understand why plate tectonics is found on Earth, but is absent on the other rocky planets of our solar system. This project supports development of a new type of rock deformation apparatus, in which specimens are subjected to torsional deformation. The particular capabilities of the Large Volume Torsion Apparatus (LVT2) enable experiments that reproduce conditions similar to those along boundaries between Earth’s tectonic plates. The LVT2 will be a uniquely capable tool for investigating the microphysics of rock deformation, rheology at plate boundaries, and the origins of seismic anisotropy in the crust and upper mantle. Previous support made possible the design and construction of the LVT2. This current project will allow the investigators, including a postdoctoral scholar, to (1) develop calibrations, techniques, and standard operating procedures, and (2) conduct preliminary experiments of scientific merit to evaluate the efficacy these procedures. Precise calibrations and robust standard operating procedures will yield a high level of safety and reliability, making rock deformation experiments more accessible to undergraduate students, external collaborators, and other short-term visitors. Support of a postdoctoral scholar will provide training to an early career scientists. Preliminary experiments to investigate the development of crystallographic preferred orientation will be used to better interpret seismic anisotropy in the mantle. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.