Magma flow inferred from anisotropy of magnetic susceptibility in the coastal Paraná-Etendeka igneous province: Evidence for rifting before flood volcanism

Abstract

Research Article| December 01, 1997 Magma flow inferred from anisotropy of magnetic susceptibility in the coastal Paraná-Etendeka igneous province: Evidence for rifting before flood volcanism Jonathan M. G. Glen; Jonathan M. G. Glen 1Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, California 94709 Search for other works by this author on: GSW Google Scholar Paul R. Renne; Paul R. Renne 1Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, California 94709 Search for other works by this author on: GSW Google Scholar Simon C. Milner; Simon C. Milner 2Geological Survey of Namibia, P.O. Box 2168, Windhoek, Republic of Namibia Search for other works by this author on: GSW Google Scholar Robert S. Coe Robert S. Coe 3Earth Sciences Department, University of California, Santa Cruz, California 95064 Search for other works by this author on: GSW Google Scholar Author and Article Information Jonathan M. G. Glen 1Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, California 94709 Paul R. Renne 1Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, California 94709 Simon C. Milner 2Geological Survey of Namibia, P.O. Box 2168, Windhoek, Republic of Namibia Robert S. Coe 3Earth Sciences Department, University of California, Santa Cruz, California 95064 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1997) 25 (12): 1131–1134. https://doi.org/10.1130/0091-7613(1997)025<1131:MFIFAO>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Jonathan M. G. Glen, Paul R. Renne, Simon C. Milner, Robert S. Coe; Magma flow inferred from anisotropy of magnetic susceptibility in the coastal Paraná-Etendeka igneous province: Evidence for rifting before flood volcanism. Geology 1997;; 25 (12): 1131–1134. doi: https://doi.org/10.1130/0091-7613(1997)025<1131:MFIFAO>2.3.CO;2 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 Paraná-Etendeka igneous province is one of the largest flood volcanic provinces in the world; peak magmatic activity at 132 Ma is believed to have occurred about 5 m.y. before the birth of south Atlantic sea floor and development of rift basins along the Brazilian coastal margin. Anisotropy of magnetic susceptibility (AMS) measurements on 283 samples (28 flows and 3 sills) from the Etendeka igneous province of Namibia and 180 samples (21 flows) from the Paraná province in Brazil reveal remarkably consistent fabric orientations with maximum susceptibility (K1) axes subhorizontal and parallel to the rifted margin. The AMS results are most likely due to shape anisotropy reflecting magma flow directions, suggesting that lava flows and intrusive conduits near the eventual rifted margin were controlled by structures having topographic expression in existence at the time of peak flood volcanism. These results imply that rifting preceded flood volcanism, at least in the portion of the magmatic province within 100 km of the nascent Mid-Atlantic Ridge. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.