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Mantle Upwelling, Continental Sutures, and LAB Structure Identified From a Suite of Seismic Data Types in the Eastern United States

Description: 

The eastern US was constructed over several Wilson cycles, with multiple continent-scale sutures preserved in the geologic record. During the breakup of Pangea, the eastern North American lithosphere was heavily modified, with implications for ongoing mantle dynamics along the margin. Previous seismological imaging has lacked needed resolution to assess how ancient boundaries and recent processes manifest throughout the lithosphere. We present a high-resolution, plate-scale seismic tomography model of the eastern US. We inverted seismic velocity using Rayleigh and Love wave phase velocity, Rayleigh wave ellipticity, and Sp and Ps receiver function data. This combination of data provides resolution from the crust to the asthenosphere, constraining both absolute velocity and the depths of velocity discontinuities. We produce maps of crustal properties, mantle velocity, lithospheric depth and mid-lithospheric discontinuities. A sharp step in lithospheric thickness at the Appalachian front explains mantle upwellings that may erode the base of the plate and shape modern Appalachian topography. We identify low-velocity structures in the lithospheric-mantle that align with the Grenville front and may be remnants of Rodinia assembly. Heavily modified lithosphere east of the Appalachians is a legacy of post-Pangean extension, CAMP magmatism, and ongoing dynamics.

Session: Earth’s Structure from the Crust to the Core - II

Type: Oral

Date: 5/1/2024

Presentation Time: 11:00 AM (local time)

Presenting Author: Brennan

Student Presenter: Yes

Invited Presentation: 

Authors