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Submarine silicic caldera at the front of the Izu-Bonin arc, Japan: Voluminous seafloor eruptions of rhyolite pumice

2001; Geological Society of America; Volume: 113; Issue: 7 Linguagem: Inglês

10.1130/0016-7606(2001)113 2.0.co;2

1943-2674

Richard S. Fiske, Jiro Naka, Kokichi Iizasa, Makoto Yuasa, Adam Klaus,

Geology and Paleoclimatology Research

Research Article| July 01, 2001 Submarine silicic caldera at the front of the Izu-Bonin arc, Japan: Voluminous seafloor eruptions of rhyolite pumice Richard S. Fiske; Richard S. Fiske 1Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA Search for other works by this author on: GSW Google Scholar Jiro Naka; Jiro Naka 2Deep Sea Research Department, Japan Marine Science and Technology Center, Yokosuka 237, Japan Search for other works by this author on: GSW Google Scholar Kokichi Iizasa; Kokichi Iizasa 3Marine Geology Department, Geological Survey of Japan, Tsukuba, Ibaraki 305, Japan Search for other works by this author on: GSW Google Scholar Makoto Yuasa; Makoto Yuasa 3Marine Geology Department, Geological Survey of Japan, Tsukuba, Ibaraki 305, Japan Search for other works by this author on: GSW Google Scholar Adam Klaus Adam Klaus 4Ocean Drilling Program, Texas A&M University, College Station, Texas 77845, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Richard S. Fiske 1Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA Jiro Naka 2Deep Sea Research Department, Japan Marine Science and Technology Center, Yokosuka 237, Japan Kokichi Iizasa 3Marine Geology Department, Geological Survey of Japan, Tsukuba, Ibaraki 305, Japan Makoto Yuasa 3Marine Geology Department, Geological Survey of Japan, Tsukuba, Ibaraki 305, Japan Adam Klaus 4Ocean Drilling Program, Texas A&M University, College Station, Texas 77845, USA Publisher: Geological Society of America Received: 12 Jan 2000 Revision Received: 03 Jul 2000 Accepted: 21 Jul 2000 First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2001) 113 (7): 813–824. https://doi.org/10.1130/0016-7606(2001)113 2.0.CO;2 Article history Received: 12 Jan 2000 Revision Received: 03 Jul 2000 Accepted: 21 Jul 2000 First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Richard S. Fiske, Jiro Naka, Kokichi Iizasa, Makoto Yuasa, Adam Klaus; Submarine silicic caldera at the front of the Izu-Bonin arc, Japan: Voluminous seafloor eruptions of rhyolite pumice. GSA Bulletin 2001;; 113 (7): 813–824. doi: https://doi.org/10.1130/0016-7606(2001)113 2.0.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 SocietyGSA Bulletin Search Advanced Search Abstract Myojin Knoll caldera, a submarine rhyolitic center 400 km south of Tokyo, is one of nine silicic calderas along the northern 600 km of the Izu-Bonin(-Ogasawara) arc and the first anywhere to receive detailed, submersible-based study. The caldera, slightly smaller than the Crater Lake structure in Oregon, is 6 × 7 km in diameter; its inner walls are 500–900 m high, and it has a remarkably flat floor at 1400 m below sea level (mbsl). The caldera collapse volume is ∼18 km3, suggesting that more than 40 km3 of pumiceous tephra may have been erupted at the time the caldera formed.Precaldera seafloor eruptions built a broad volcanic edifice consisting of overlapping composite volcanoes made of rhyolitic lavas, shallow intrusions, and a variety of volcaniclastic deposits—including thick accumulations of rhyolitic pumice erupted at 900– 500 mbsl. The caldera-forming eruption produced a 150–200 m deposit of nonwelded, fines-depleted pumice that resembles a colossal layer of popcorn at the top of the caldera wall.Freshly erupted pumice behaved as "sinkers" or "floaters," depending on the environment in which it cooled. The pumice clasts deposited proximally and exposed in the caldera wall were likely quenched in eruption columns that remained below sea level. This pumice ingested seawater and sank as gases filling its vesicles cooled, particularly as steam in its vesicles condensed to liquid water. Some eruption columns may have broken through the sea surface and entered the air, especially during vigorous phases of the caldera-forming eruption. These pumices had the opportunity to ingest air as they cooled, becoming floaters as they fell back to the sea; these could have been carried distally on the sea surface by the combined effects of ocean currents and wind.The age of the caldera is unknown, but it may be as young as several thousand years. Its magmatic system at depth retains sufficient heat to sustain an actively growing intracaldera Kuroko- type polymetallic sulfide deposit, rich in gold and silver and topped by chimneys emitting fluids as hot as 278 °C. Sufficient time has elapsed, however, for a 250-m-high postcaldera dome to grow on the caldera floor and for the caldera rim to be deeply scalloped by slumping. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.