|
|||||
|
|
Open-system degassing of sulfur from Krakatau 1883 magma |
|
| Authors: | Charles W Mandeville Akira Sasaki Genji Saito Kevin Faure Robert King Erik Hauri |
| Institution: | a Department of Earth and Planetary Sciences, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA b Geological Survey of Japan, 1-1-3 Higashi, Tsukuba, Ibaraki 305, Japan c Instituto de Geologia de Geologia Economica Aplicada, Universidad de Concepcion, Casilla 4107, Concepcion 3, Chile d Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road N.W., Washington, DC 20015, USA |
| Abstract: | We present the first sulfur and oxygen isotopic data for tephra from the catastrophic 1883 eruption of Krakatau. Sulfur isotopic ratios in unaltered Krakatau tephra erupted August 26–27, 1883 are markedly enriched in 34S relative to mantle sulfur. High δ34S values of +6.3 to +16.4‰ can best be explained by open-system or multi-stage degassing of SO2 from the oxidized rhyodacitic and gray dacitic magmas with 34S enrichment of SO2−4 remaining in the melt. Lower whole-rock δ34S values of +2.6‰ and +4.0‰ in two oxidized gray dacitic samples indicate more primitive subarc mantle sulfur in the 1883 magma chamber. Initial δ34S of the rhyodacitic magma was probably in the +1.5‰ to +4.0‰ range and similar to δ34S values measured in arc volcanic rocks from the Mariana Arc. |
| Keywords: | pyroclastics sulfur degassing Krakatoa |
| 本文献已被 ScienceDirect 等数据库收录！ | |