12-3 The Nodal NEST: Imaging the Laurentia-Appalachian suture of northwestern Massachusetts and Vermont from the surface to mantle using a high-density nodal seismic transect

Session: New advances in geological and geophysical research on the Appalachian orogen. (II)

Presenting Author:

James Bourke

Authors:

Bourke, James¹, Long, Maureen², Karabinos, Paul³, Webb, Laura E.⁴, Sheridan, Heather⁵, Gulick, Clara⁶, Smith, Chrishera⁷, Macleod, Lawrence⁸, Hagan, Ciara⁹, Bohling, Amelia¹⁰

(1) Earth and Planetary Sciences, Yale University, New Haven, , (2) Yale University, New Haven, , (3) Williams College, Williamstown, , (4) University of Vermont, Burlington, , (5) Williams College, , (6) Yale University, , (7) Florida Atlantic University, , (8) University of Vermont, , (9) University of Vermont, , (10) University of Vermont, ,

Abstract:

The New England Appalachians provide a fascinating window into a host of fundamental geologic phenomena. These include modification of the crust and mantle lithosphere through repeated episodes of orogenesis, terrane accretion, and continental rifting throughout New England. Recent (SEISConn, 2016-2019; GENESIS, 2021-2025) and ongoing (NEST, 2018-Present) temporary seismological experiments have revealed the lithospheric structure in unprecedented detail, however their spatial extent (~10 - 20 km spacing) has restricted the analysis to deeper crust and upper mantle imaging, limiting our connections between the surficial bedrock geology and the well-imaged deeper structures. In this study, we present our most recent seismological deployment of ~200 short-period nodal seismometers in higher density spacing (< 500m) attempting to trace geologic structures at the surface into their projections at depth. Our deployment consists of two ~50 km long linear transects in northwestern Massachusetts and Vermont, crossing the suture between Laurentia and the Appalachian terranes. We seek to image the uppermost geologic structures using a suite of imaging techniques, present initial results, and discuss on-going geologic targets for imaging and hypothesis testing.  We highlight successes, lessons learned, and pitfalls experienced while conducting our most recent higher density seismological deployment. This work will reveal how Appalachian orogenesis and subsequent Mesozoic rifting events are expressed in the upper crustal structure, how well that structure is preserved over geologic time, and the relative importance of different tectonic processes in shaping the crust. These comparisons will yield a comprehensive picture of how Paleozoic Appalachian orogenesis, Mesozoic rifting and continental breakup, and later tectonic adjustments have shaped, reworked, or masked the suture zones and other features preserved in the upper crust beneath New England.

Geological Society of America Abstracts with Programs. Vol. 58, No. 2, 2026

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