Along-margin variations in breakup volcanism at the Eastern North American Margin

Journal of Geophysical Research
By: , and 

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Abstract

We model the magnetic signature of rift-related volcanism to understand the distribution and volumeofmagmatic activity that occurred during the breakup of Pangaea and early Atlantic opening at the Eastern North American Margin (ENAM).Along-strike variations in the amplitude and character of the prominent East Coast Magnetic Anomaly (ECMA) suggest that the emplacement of the volcanic layers producing this anomaly similarly varied along the margin. We use three-dimensional magnetic forward modeling constrained by seismic interpretationsto identify along-margin variations in volcanic thickness and width that can explain the observed amplitude and character of the ECMA. Our model results suggest that the ECMA is produced by a combination of both first-order (~600-1000 km)and second-order (~50-31100 km) magmatic segmentation. The first-order magmatic segmentation could have resulted from preexisting variations in crustal thickness and rheology developed during the tectonic amalgamation of Pangaea. The second-order magmatic segmentation developed during continental breakup and likely influenced the segmentation and transform fault spacing of the initial, and modern, Mid-Atlantic Ridge. These variations in magmatism showhow extension and thermal weakening was distributed at the ENAM during continental breakup and how this breakup magmatism was related to both previous and subsequent Wilson Cycle stages.

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Publication type Article
Publication Subtype Journal Article
Title Along-margin variations in breakup volcanism at the Eastern North American Margin
Series title Journal of Geophysical Research
DOI 10.1029/2020JB020040
Volume 125
Issue 12
Year Published 2020
Language English
Publisher American Geophysical Union
Contributing office(s) Woods Hole Coastal and Marine Science Center
Description e2020JB020040
Country United States
Other Geospatial East Coast of United States, Atlantic Ocean
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