Modeling the Geophysical Signatures of Gneiss Dome Exhumation in the Northeast United States
Abstract
Gneiss domes are relatively common structures in orogenic terranes. They can form from a variety of deformation and exhumation mechanisms, and it can be difficult to distinguish between potential exhumation mechanisms because surface structures can be similar for different mechanisms. The interior structure of a gneiss dome may provide more unique information if it can be captured using geophysical methods. Gneiss domes may contain rock types with contrasting geophysical properties, but the interior composition is likely heterogeneous at length-scales smaller than the resolution of geophysical methods. However, the deformation fabric within gneiss domes is pervasive, and penetrates all rock types. If deformation fabric can be imaged using geophysical methods, then perhaps the interior structure of gneiss domes can be identified and used to understand exhumation mechanisms.
For deformed rocks, the anisotropic seismic and magnetic properties are often related to the rock deformation fabric. It may thus be possible to map deformation fabric using anisotropy. Here we focus on making predictions of geophysical signatures based on a simplified model subsurface structure for the Chester gneiss dome in southeast Vermont. We use previously characterized elastic and magnetic (AMS) tensors from Chester dome rocks to produce model structures based on different exhumation mechanisms. We will use these models to make basic predictions of how the different structures may appear in geophysical studies, with a focus on shear-wave splitting, receiver functions, and magnetic susceptibility.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMDI11A..08B
- Keywords:
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- 3902 Creep and deformation;
- MINERAL PHYSICSDE: 7208 Mantle;
- SEISMOLOGYDE: 8120 Dynamics of lithosphere and mantle: general;
- TECTONOPHYSICSDE: 8170 Subduction zone processes;
- TECTONOPHYSICS