30 New advances in geological and geophysical research on the Appalachian orogen. (Posters)

We invite contributions that discuss new research on the Appalachian orogen. Submissions should include, but are not limited to, geological or geophysical studies or works comprising a combination of both methods.

Monday, 23 March 2026
1:30 PM - 5:30 PM
CCC, Ballroom C

Investigating crustal anisotropy beneath Newfoundland and surrounding areas via receiver function analysis

Paper number: 30-6
Program: Technical Sessions
Time: 1:30 PM – 1:30 PM

Authors

Abstract

The tectonic setting of Newfoundland, part of the northern Appalachian Mountains, is defined by accreted terranes from the Paleozoic. Going west to east, there is a transition from Laurentia, part of cratonic North America, to the younger accreted terranes of Ganderia and Avalonia. In Newfoundland, boundaries between these terranes are particularly well defined, making the island an excellent region to investigate the complexities of Appalachian lithospheric structures and how they relate to the bedrock geology. Newfoundland is the target of an ongoing broadband seismic experiment to image the structure of the lithosphere, known as the Passive Array for Critical Minerals on the Island of Newfoundland (PACMIN), which is deploying 22 broadband seismic stations across Newfoundland between 2025 and 2027.

As part of the preparatory work for the PACMIN project, we are using data from the two permanent broadband seismic stations in Newfoundland to carry out initial investigations of anisotropic layering within the crust and mantle lithosphere. Observations of seismic anisotropy are a powerful tool for probing deformation within the crust and uppermost mantle due to past tectonic processes such as terrane accretion, orogenesis, and continental rifting. Previous investigations of layered crustal anisotropy elsewhere in the Appalachians have found evidence for complex structures due to subduction, terrane accretion, and orogenic plateau collapse, shedding light on the deformation response to tectonic processes. Here we apply receiver function (RF) analysis, which involves the examination of P-to-S converted seismic waves as boundaries within the lithosphere, including the Moho. We investigate the directionally dependent behavior of RFs, enabling us to characterize anisotropic layers and dipping interfaces at depth. 

Initial results from two permanent stations in Newfoundland reveal robust evidence for multiple distinct layers of anisotropy at depth, which produce strong azimuthal dependence of RF behavior. We see distinct differences in the character of the RFs between Laurentia and the Avalon terrane, with a clearer delineation of multiple anisotropic layers within the Laurentian lithosphere. We are currently expanding our analysis to examine surrounding regions in Québec, New Brunswick, and Nova Scotia to provide better regional context for anisotropic layering within the lithosphere throughout the Appalachians. Our results will also provide context for the analysis of data from the PACMIN experiment, which will return its first year of data in summer 2026.

Geological Society of America Abstracts with Programs. Vol. 58, No. 2

doi: 10.1130/abs/2026NE-411472

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