A nanolite record of eruption style transition

Research Article| July 01, 2014 A nanolite record of eruption style transition Mayumi Mujin; Mayumi Mujin Department of Earth Science, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aobaku, Sendai 980-8578, Japan Search for other works by this author on: GSW Google Scholar Michihiko Nakamura Michihiko Nakamura Department of Earth Science, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aobaku, Sendai 980-8578, Japan Search for other works by this author on: GSW Google Scholar Author and Article Information Mayumi Mujin Department of Earth Science, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aobaku, Sendai 980-8578, Japan Michihiko Nakamura Department of Earth Science, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aobaku, Sendai 980-8578, Japan Publisher: Geological Society of America Received: 07 Feb 2014 Revision Received: 24 Apr 2014 Accepted: 28 Apr 2014 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2014 Geological Society of America Geology (2014) 42 (7): 611–614. https://doi.org/10.1130/G35553.1 Article history Received: 07 Feb 2014 Revision Received: 24 Apr 2014 Accepted: 28 Apr 2014 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Tools Icon Tools Get Permissions Search Site Citation Mayumi Mujin, Michihiko Nakamura; A nanolite record of eruption style transition. Geology 2014;; 42 (7): 611–614. doi: https://doi.org/10.1130/G35553.1 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 Microlite characteristics have been successfully used as indicators of magma decompression rate. However, microlites do not record the explosive-effusive transitions in sub-Plinian eruptions, when such transitions are governed by the decrease of exsolved volatile pressure in the shallow conduit rather than by the magma ascent rate. To overcome this limitation, we studied the nanolites in the quenched products of the 2011 Shinmoedake (Japan) eruption. Nanolites are nanometer-scale components of the groundmass minerals and exhibit a steeper slope of crystal size distribution than that of microlites. In the 2011 eruption, the style of activity had undergone transformation from sub-Plinian eruption to Vulcanian explosion and intermittent effusion of lava. We found that, although the products formed by different eruptive activities have similar microlite characteristics, such products can be distinguished clearly by their mineral assemblage of nanolites. The samples of pumice of sub-Plinian eruptions and Vulcanian explosions and the dense juvenile fragments of lava (in descending order of explosivity) contained, respectively, nanolites of low-Ca pyroxene, low-Ca pyroxene + plagioclase, and low-Ca pyroxene + plagioclase + Fe-Ti oxides. Nanolites crystallize when undercooling of the magma due primarily to dehydration increases rapidly near the surface. The water contents of the interstitial glass indicate that the quenched depths did not differ greatly between eruption styles. Hence, the different nanolite assemblages of each eruption style are assumed to have resulted from differences in magma residence time near the surface. Therefore, we propose that nanolites have the potential to indicate the physicochemical conditions of magma at the transition points of eruption styles. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.