Lithospheric Structure in the Southeastern US using Reverberation-Corrected Receiver Functions
Abstract
The Southeastern United States (SEUS) lies on the passive eastern North American margin and preserves a long geologic record of continental collision, rifting, and volcanism. The multiple episodes of continental collisions have left a chaotic assortment of accreted terranes and faults. The lithospheric structure reflecting these accreted terranes documents the evolution of the SEUS. Weaknesses in the lithosphere inherited from these past collisional events are a proposed explanation for the intraplate seismicity of this passive margin; however, the extent and magnitude of intra-lithospheric variations in the SEUS in relation to the intraplate seismicity has not been fully explored. Therefore, mapping variations in lithospheric structure will help clarify the tectonic history of the region and highlight possible mechanisms of intraplate seismicity.
Typically, P-to-s receiver functions are used to constrain interfaces in the lithosphere, but their application to the SEUS has proven difficult as reverberations in the Atlantic coastal plain and basins may overprint deeper crustal and lithospheric structure. Here, we use reverberation-corrected P-to-s receiver functions (PRFs), combined with S-to-p receiver functions (SRFs), to constrain crustal and lithospheric variations across the entire SEUS. We find evidence for deep mid-crustal layering (or a "double-Moho") deepening westward beneath the Blue Ridge in eastern Tennessee as well as a shallow mid-crustal layer deepening eastward which has been interpreted to mark the location of the suture between Laurentia and Gondwana during the formation of Pangea ( Hopper et al. 2017 ). We find no evidence for a strong lithosphere-asthenosphere boundary or mid-lithospheric discontinuities associated with the location of intra-crustal earthquakes.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMDI13B0006C
- Keywords:
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- 7218 Lithosphere;
- SEISMOLOGY;
- 7218 Lithosphere;
- SEISMOLOGY;
- 8103 Continental cratons;
- TECTONOPHYSICS;
- 8103 Continental cratons;
- TECTONOPHYSICS;
- 8110 Continental tectonics: general;
- TECTONOPHYSICS;
- 8110 Continental tectonics: general;
- TECTONOPHYSICS;
- 8120 Dynamics of lithosphere and mantle: general;
- TECTONOPHYSICS;
- 8120 Dynamics of lithosphere and mantle: general;
- TECTONOPHYSICS;
- 8120 Dynamics of lithosphere and mantle: general;
- TECTONOPHYSICS;
- 8120 Dynamics of lithosphere and mantle: general;
- TECTONOPHYSICS;
- 8124 Earth's interior: composition and state;
- TECTONOPHYSICS;
- 8124 Earth's interior: composition and state;
- TECTONOPHYSICS;
- 8170 Subduction zone processes;
- TECTONOPHYSICS;
- 8170 Subduction zone processes;
- TECTONOPHYSICS