Integration of COCORP deep reflection and magnetic anomaly analysis in the southeastern United States: Implications for origin of the Brunswick and East Coast magnetic anomalies: Alternative interpretation and reply

Geological Society of America Bulletin
By: , and 

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Abstract

Integration of magnetic anomaly analysis with COCORP deep reflection data from the southeastern United States provides three new constraints on the interpretation of the Brunswick and East Coast magnetic anomalies, as well as on the reflection data. These are as follows. (1) The source of the Brunswick anomaly lies within the deep crust. This anomaly is not caused by a Mesozoic rift basin, as proposed by some workers. (2) A simple, seaward-dipping, high- susceptibility slab model can explain both the Brunswick and East Coast magnetic anomalies. The along-strike change in character of the two anomalies results largely from a change in azimuth of the source body. (3) Beneath the southeastern United States, this source body dips south, lies immediately on the south flank of the prominent southward-dipping reflective zone revealed on COCORP surveys, and was previously associated with the Alleghanian suture between North America and Africa. These results imply that a dipping, highly magnetized zone in the upper plate of the Alleghanian suture is responsible for both the Brunswick and East Coast magnetic anomalies. The high- susceptibility material responsible for these anomalies might be mafic lower continental or oceanic crust thrust upward during Alleghanian continental collision, or mafic igneous material intruded into the upper plate of the suture zone during subsequent Mesozoic rifting, or both. The latter hypothesis implies that the Alleghanian suture acted, as a zone of weakness (a repository ?) which was reactivated to control the site of ultimate Atlantic rifting and possibly initial sea-floor spreading.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Integration of COCORP deep reflection and magnetic anomaly analysis in the southeastern United States: Implications for origin of the Brunswick and East Coast magnetic anomalies: Alternative interpretation and reply
Series title Geological Society of America Bulletin
DOI 10.1130/0016-7606(1990)102<0271:IOCDRA>2.3.CO;2
Volume 102
Issue 2
Year Published 1990
Language English
Publisher Geological Society of America
Contributing office(s) Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center
Description 9 p.
First page 271
Last page 279
Online Only (Y/N) N
Additional Online Files (Y/N) N