The Effects of Simple Shear Strain on Remanence

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This is a project to conduct a detailed rock magnetic and finite strain study to determine whether rock strain during folding is typically of the correct magnitude and geometry to rotate a prefolding magnetization into a synfolding configuration. The effects of layer parallel simple shear strain on remanence-carrying grains will be investigated through field investigations and laboratory modeling experiments. In the field component of this project, the PI will study the finite strain and remanence in several mid-Paleozoic Appalachian clastic rocks from the Valley and Ridge Province which are known to carry stable signals (eg. Bloomsburg Formation, Juniata Formation, Rose Hill Formation). The finite strain of some of these rocks has been studied (eg. green reduction spots in the Bloomsburg Formation). The results of these studies will be extended by the investigation of progressive, noncoaxial deformation recorded by syntectonic pressure fibers around rigid grains and/or in syntectonic extension veins. Sampling schemes will be designed to compare the remanence in strained and unstrained rocks to detect rotation of remanence. In the laboratory component of this study, the PI will deform a synthetic magnetic sediment by simple shear strain to determine the effects of a well- controlled, constant volume, noncoaxial deformation on remanence- carrying grains.