Volcanoes of the passive margin: The youngest magmatic event in eastern North America

Abstract

Research Article| June 01, 2014 Volcanoes of the passive margin: The youngest magmatic event in eastern North America Sarah E. Mazza; Sarah E. Mazza 1Department of Geosciences, Virginia Polytechnic Institute and State University, 4044 Derring Hall (0420), Blacksburg, Virginia 24061, USA Search for other works by this author on: GSW Google Scholar Esteban Gazel; Esteban Gazel * 1Department of Geosciences, Virginia Polytechnic Institute and State University, 4044 Derring Hall (0420), Blacksburg, Virginia 24061, USA *E-mail: [e-mail]. Search for other works by this author on: GSW Google Scholar Elizabeth A. Johnson; Elizabeth A. Johnson 2Department of Geology and Environmental Science, James Madison University, MSC 6903 Memorial Hall, Harrisonburg, Virginia 22807, USA Search for other works by this author on: GSW Google Scholar Michael J. Kunk; Michael J. Kunk 3U.S. Geologic Survey, 12201 Sunrise Valley Drive, MS 926A, Reston, Virginia 20192-0002, USA Search for other works by this author on: GSW Google Scholar Ryan McAleer; Ryan McAleer 3U.S. Geologic Survey, 12201 Sunrise Valley Drive, MS 926A, Reston, Virginia 20192-0002, USA Search for other works by this author on: GSW Google Scholar James A. Spotila; James A. Spotila 1Department of Geosciences, Virginia Polytechnic Institute and State University, 4044 Derring Hall (0420), Blacksburg, Virginia 24061, USA Search for other works by this author on: GSW Google Scholar Michael Bizimis; Michael Bizimis 4Department of Earth and Ocean Sciences, University of South Carolina, 701 Sumter Street, EWS 617, Columbia, South Carolina 29208, USA Search for other works by this author on: GSW Google Scholar Drew S. Coleman Drew S. Coleman 5Department of Geological Sciences, University of North Carolina Chapel Hill, CB#3315, Chapel Hill, North Carolina 27599, USA Search for other works by this author on: GSW Google Scholar Geology (2014) 42 (6): 483–486. https://doi.org/10.1130/G35407.1 Article history received: 21 Dec 2013 rev-recd: 05 Mar 2014 accepted: 06 Mar 2014 first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Sarah E. Mazza, Esteban Gazel, Elizabeth A. Johnson, Michael J. Kunk, Ryan McAleer, James A. Spotila, Michael Bizimis, Drew S. Coleman; Volcanoes of the passive margin: The youngest magmatic event in eastern North America. Geology 2014;; 42 (6): 483–486. doi: https://doi.org/10.1130/G35407.1 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 The rifted eastern North American margin (ENAM) provides important clues to the long-term evolution of continental margins. An Eocene volcanic swarm exposed in the Appalachian Valley and Ridge Province of Virginia and West Virginia (USA) contains the youngest known igneous rocks in the ENAM. These magmas provide the only window into the most recent deep processes contributing to the postrift evolution of this margin. Here we present new 40Ar/39Ar ages, geochemical data, and radiogenic isotopes that constrain the melting conditions and the timing of emplacement. Modeling of the melting conditions on primitive basalts yielded an average temperature and pressure of 1412 ± 25 °C and 2.32 ± 0.31 GPa, corresponding to a mantle potential temperature of ∼1410 °C, suggesting melting conditions slightly higher than average mantle temperatures beneath mid-ocean ridges. When compared with magmas from Atlantic hotspots, the Eocene ENAM samples share isotopic signatures with the Azores and Cape Verde. This similarity suggests the possibility of a large-scale dissemination of similar sources in the upper mantle left over from the opening of the Atlantic Ocean. Asthenosphere upwelling related to localized lithospheric delamination is a possible process that can explain the intraplate signature of these magmas that lack evidence of a thermal anomaly. This process can also explain the Cenozoic dynamic topography and evidence of rejuvenation of the central Appalachians. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.