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The Continental Collision and Rifting in East North America Margin Revealed by Full Waveform Tomography

Description: 

The East North America Margin (ENAM) represent a passive continental margin that has undergone several stages of collision and rifting throughout geological history. Notably, the formation and breakup of Rodinia and later, the assembly and breakup of Pangea. The strong collision resulted in the uplift of the Appalachian Mountains, while the period of extension was accompanied by extensive magma upwelling and the formation of sedimentary basins. The complex geological history makes the ENAM an ideal natural laboratory for studying continental collision and rifting processes. Our study focuses on several regions with dense array deployment, and they are SESAME array (Parker et al., 2013) in Southern Appalachians, MAGIC array (Long et al., 2020) in central Appalachians and SEISConn array (Long and Aragon, 2020) in northern Appalachians. With three case studies, we aim to compare the similarities and differences in the evolution at different locations along ENAM.

We employed a joint full-waveform inversion (FWI) approach utilizing ambient noise data and teleseismic data based on the precise 3D Spectral Element Method (SEM) solver. This methodology enabled the creation of high-resolution isotropic shear wave velocity models in the three regions. Upon comparing these models, we observed a consistent variation in Moho depth along the Appalachians. Notably, the central and northern Appalachians exhibited a more pronounced depth variation than the southern Appalachians. Additionally, we investigated the anisotropic structure of these regions, revealing robust positive radial anisotropy along the terrane boundaries in all three areas, likely resulting from the Mesozoic rifting event. Nevertheless, the anisotropy pattern differed between the southern and northern Appalachians, suggesting distinct collision and splitting dynamics. The inverted models provide intricate subsurface insights beneath ENAM and represent a valuable dataset to enhance our comprehension of continental collision and rifting processes.

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

Type: Oral

Date: 5/1/2024

Presentation Time: 02:00 PM (local time)

Presenting Author: Ting

Student Presenter: Yes

Invited Presentation: 

Authors