Explosive subglacial rhyolitic eruptions in Iceland are fuelled by high magmatic H2O and closed-system degassing

Abstract

Research Article| February 01, 2013 Explosive subglacial rhyolitic eruptions in Iceland are fuelled by high magmatic H2O and closed-system degassing Jacqueline Owen; Jacqueline Owen 1Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK Search for other works by this author on: GSW Google Scholar Hugh Tuffen; Hugh Tuffen 1Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK Search for other works by this author on: GSW Google Scholar David W. McGarvie David W. McGarvie 2Department of Environment, Earth and Ecosystems, The Open University, Milton Keynes MK7 6AA, UK Search for other works by this author on: GSW Google Scholar Author and Article Information Jacqueline Owen 1Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK Hugh Tuffen 1Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK David W. McGarvie 2Department of Environment, Earth and Ecosystems, The Open University, Milton Keynes MK7 6AA, UK Publisher: Geological Society of America Received: 18 May 2012 Revision Received: 13 Aug 2012 Accepted: 12 Sep 2012 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2013 Geological Society of America Geology (2013) 41 (2): 251–254. https://doi.org/10.1130/G33647.1 Article history Received: 18 May 2012 Revision Received: 13 Aug 2012 Accepted: 12 Sep 2012 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Jacqueline Owen, Hugh Tuffen, David W. McGarvie; Explosive subglacial rhyolitic eruptions in Iceland are fuelled by high magmatic H2O and closed-system degassing. Geology 2013;; 41 (2): 251–254. doi: https://doi.org/10.1130/G33647.1 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 Rhyolitic eruptions beneath Icelandic glaciers can be highly explosive, as demonstrated by Quaternary tephra layers dispersed throughout northern Europe. However, they can also be small and effusive. A subglacial rhyolitic eruption has never been observed, so behavioral controls remain poorly understood and the influence of pre-eruptive volatile contents is unknown. We have therefore used secondary ion mass spectrometry to characterize pre-eruptive volatile contents and degassing paths for five subglacial rhyolitic edifices within the Torfajökull central volcano, formed in contrasting styles of eruption under ice ∼400 m thick. This includes the products of the largest known eruption of Icelandic subglacial rhyolite of ∼16 km3 at ca. 70 ka. We find pre-eruptive water contents in melt inclusions (H2OMI) of up to 4.8 wt%, which indicates that Icelandic rhyolite can be significantly more volatile-rich than previously thought. Our results indicate that explosive subglacial rhyolite eruptions correspond with high H2OMI, closed-system degassing, and rapid magma ascent, whereas their effusive equivalents have lower H2OMI and show open-system degassing and more sluggish ascent rates. Volatile controls on eruption style thus appear similar to those for subaerial eruptions, suggesting that ice plays a subsidiary role in influencing the behavior of subglacial rhyolitic eruptions. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.