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Title: Lithospheric Structure in the Northern Appalachian Mountains: A Detailed Examination of the Abrupt Change in Crustal Thickness in Northwestern Massachusetts
Abstract

Previous geophysical studies in the New England Appalachians identified a ∼15 km offset in crustal thickness near the surface boundary between Laurentia and the accreted terranes. Here, we investigate crustal structure using data from a denser array: New England Seismic Transects experiment, which deployed stations spaced ∼10 km apart across the Laurentia‐Moretown terrane suture in northwestern Massachusetts. We used receiver function (RF) analysis to detectPtoSVconverted waves and identified multiple interfaces beneath the transect. We also implemented a harmonic decomposition analysis to identify features at or near the Moho with dipping and/or anisotropic character. Beneath the Laurentian margin, the Ps converted phase from the Moho arrives almost 5.5 s after the initialPwave, whereas beneath the Appalachian terranes, the pulse arrives at 3.5 s, corresponding to ∼48 and ∼31 km depth, respectively. The character of the RF traces beneath stations in the middle of our array suggests a complex transitional zone with dipping and/or anisotropic boundaries extending at least ∼30 km. This extension is measured in our profiles and perpendicular to the suture. We propose one possible crustal geometry model that is consistent with our observations and results from previous studies.

 
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Award ID(s):
2147536
PAR ID:
10564814
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
American Geophysical Union
Date Published:
Journal Name:
Geochemistry, Geophysics, Geosystems
Volume:
25
Issue:
10
ISSN:
1525-2027
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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