Explosive Deep Water Basalt in the Sumisu Backarc Rift

• DOI: 10.1126/science.248.4960.1214
• Publication Date: 2006-10-05T22:10:14Z
• Authors: J. Gill; P. Torssander; H. Lapierre; R. Taylor; K. Kaiho; M. Koyama; M. Kusakabe; J. Aitchison; S. Cisowski; K. Dadey; K. Fujioka; A. Klaus; M. Lovell; K. Marsaglia; P. Pezard; B. Taylor; K. Tazaki
• Keywords: Subaerial; Breccia; Rift zone

Eruption of 1-million-year-old tholeiitic basalt >1800 meters below sea level (>18 megapascals) in a backarc rift behind the Bonin arc produced scoriaceous breccia similar some respects to that formed during subaerial eruptions. Explosion magma is thought have frothy agglutinate which welded either on floor or submarine eruption column. The resulting 135-meter-thick pyroclastic deposit has paleomagnetic inclinations are random at scale <2.5 meters. High magmatic water content, about 1.3 percent by weight after vesiculation, contributed explosivity.