The Brunswick magnetic anomaly: Geophysical signature and geologic source

Abstract

Research Article| February 28, 2019 The Brunswick magnetic anomaly: Geophysical signature and geologic source Patrick D. Duff; Patrick D. Duff 1School of Earth, Ocean, and Environment, University of South Carolina, Columbia, South Carolina 29208, USA Search for other works by this author on: GSW Google Scholar James N. Kellogg James N. Kellogg 1School of Earth, Ocean, and Environment, University of South Carolina, Columbia, South Carolina 29208, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Patrick D. Duff 1School of Earth, Ocean, and Environment, University of South Carolina, Columbia, South Carolina 29208, USA James N. Kellogg 1School of Earth, Ocean, and Environment, University of South Carolina, Columbia, South Carolina 29208, USA Publisher: Geological Society of America Received: 08 Aug 2018 Revision Received: 27 Jan 2019 Accepted: 29 Jan 2019 First Online: 28 Feb 2019 Online Issn: 1943-2682 Print Issn: 0091-7613 © 2019 Geological Society of America Geology (2019) 47 (4): 355–358. https://doi.org/10.1130/G45462.1 Article history Received: 08 Aug 2018 Revision Received: 27 Jan 2019 Accepted: 29 Jan 2019 First Online: 28 Feb 2019 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Patrick D. Duff, James N. Kellogg; The Brunswick magnetic anomaly: Geophysical signature and geologic source. Geology 2019;; 47 (4): 355–358. doi: https://doi.org/10.1130/G45462.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract We used integrated analyses and forward and inverse modeling of potential field data to interpret the enigmatic Brunswick magnetic anomaly (BMA), a prominent negative magnetic lineation that is developed within the ocean-continent transition of the Southeast Georgia Embayment. From magnetic profiles extracted from gridded data, residual magnetic maps, and simultaneous 2.5-dimensional forward and 3-dimensional Euler inverse modeling of the gravity and magnetic fields, we suggest that the source of the BMA is a series of semicontinuous to discrete, late-stage rift-related mafic intrusions of Mesozoic age. This interpretation is supported by the observation that the BMA is independent of the East Coast magnetic anomaly, implying a predrift source, and that the amplitude and frequency of the anomaly change nearshore across a fracture zone that divides the offshore BMA, where continental breakup occurred, from the onshore BMA. Modeling demonstrates for the first time that a Mesozoic rift-related mafic body can explain the anomaly onshore. The lack of a BMA equivalent on the West African margin may indicate that Atlantic rifting began with a single lithospheric dislocation. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.