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Volcanic-related alteration and geochemistry of Iwodake volcano, Satsuma-Iwojima, Kyushu, SW Japan
Earth, Planets and Space volume 54, pages217–229(2002)
Satsuma-Iwojima is located near the northwestern margin of Kikai caldera, and active Mt. Iwodake is one of the post-caldera cones. Inside the summit crater of about 300 m diameter and 50 m depth, volcanic gas with maximum temperature >800°C is discharged. At Iwodake, the rhyolite is strongly altered by volcanic vapor and acid hydrothermal solution inside and around the summit crater. The main alteration mineral assemblages at surface include quartz-tridymite-cristobalite, tridymite-cristobalite-alunite and cristobalite-(alunite) inside the summit crater and on the flank. Molybdenum blue sublimates are forming at the surface around high-temperature fumaroles inside the summit crater. The ground surface is commonly cemented by amorphous silica or cristobalite. The original rhyolite with SiO2 = 71–72 wt% has been leached, resulting in a rock with maximum SiO2 = 97 wt%. All major elements are leached except for TiO2. Although LIL (large-ion lithophile) elements have leached, HFS (high field-strength) elements appear to be immobile. Rare earth elements are considered to have been soluble as a complex with sulfate mainly in the low pH hydrothermal fluid during the silicification of the rhyolite. There is abundant Mo, Pb, Zn, Bi, Sn and much lower As in the volcanic sublimates and altered rocks inside the summit crater. By contrast, the rocks near the acid springs at the foot of the cone are As-rich, but with lower Pb, Zn, Bi and little Mo in comparison with the summit. The fractures and fumarole locations around Iwodake summit and erosional ridges on the flanks reflects a NE-SW trend that is parallel to the trace of the outer ring of Kikai caldera. In addition, this is the same direction as the alignment of Shin-Iwojima, Iwodake and Inamuradake, all of which are post-caldera cones. Zones of structural weakness parallel to the caldera rim may exist, acting as pathways for the ascending volcanic gases and hydrothermal solutions. Fumarolic activity appears to be shifting gradually to the eastern part of the summit crater.
Arribas, A., Jr., C. G. Cunninham, J. J. Rytuba, R. O. Rye, W. C. Kelly, M. H. Podwisocki, E. H. McKee, and R. M. Tosdal, Geology, geochronology, fluid inclusions, and isotope geochemistry of the Rodalquilar gold alunite deposit, Spain, Economic Geology, 90, 795–822, 1995.
Christenson, B. W. and C. P. Wood, Evolution of a vent-hosted hydrothermal system beneath Ruapehu Crater Lake, New Zealand, Bulletin of Volcanology, 55, 547–565, 1993.
Fulignati, P., A. Gioncada, and A. Sbrana, Rare-earth element (REE) behaviour in the alteration facies of the active magmatic-hydrothermal systm of Vulcano (Aeolian Islands, Italy), J. Volcanol. Geotherm. Res., 88, 325–342, 1999.
G.S.J. (Geological Survey of Japan) and Kyoto University, Recent volcanic activity at the summit of Iwodake, Satsuma-Isojima until Nov. 1997, Report of Coordinating Committee for Prediction of Volcanic Eruption, 70, 59–61, 1998 (in Japanese).
Hamasaki, S., The distribution and direction of the alteration zone in and around the crater at Satsuma-Iwojima volcano, Program and abstracts, The Volcanological Society of Japan, 1999, 2, 90, 1999 (in Japanese).
Hedenquist, J. W., M. Aoki, and H. Shinohara, Flux of volatiles and ore-forming metals from the magmatic hydrothermal system of Satsuma Iwojima volcano, Geology, 22, 585–588, 1994a.
Hedenquist, J. W., Y. Matsuhisa, E. Izawa, N. White, W. F. Giggenbach, and M. Aoki, Geology, geochemistry, and origin of high sulfidation Cu-Au mineralization in the Nansatsu district, Japan, Economic Geology, 89, 1–30, 1994b.
Hemley, J. J., P. B. Hostetler, A. J. Gude, and W. T. Mountjoy, Some stability relations of alunite, Economic Geology, 64, 599–612, 1969.
Johannesson, K. H. and W. B. Lyons, Rare-earth element geochemistry of Colour Lake, an acidic freshwater lake on Axel Heiberg Island, Northwest Territories, Canada, Chemical Geology, 119, 209–223, 1995.
Kamada, M., H. Sakamoto, and T. Onishi, Geochemical studies on Iwo-jima volcano (Kagoshima Pref.) Part 1. Chemical composition, temperature, and discharge of Higashi hot spring, and their variation, Onsenkougakukaisi, 9, 117–124, 1974 (in Japanese with English abstract).
Kawanabe, Y., 14C dating of the Io-dake pyroclastic flow deposits, Satsuma Iojima volcano, Japan, Report of Coordinating Committee for Prediction of Volcanic Eruption, 75, 115, 2000 (in Japanese).
Kimbara, K., H. Shigeno, and T. Okubo, Hydrothermal alteration of Satsuma-Iwojima, Chishitsu News, 272, 9–17, 1977 (in Japanese).
Lewis, A. J., M. R. Palmer, N. C. Sturchio, and A. J. Kemp, The rare earth element geochemistry of acid-sulphate and acid-sulphate-chloride geothermal systems from Yellowstone National Park, Geochim. Cosmochim. Acta, 61, 695–706, 1997.
Lewis, A. J., A. Komninou, B. W. Yardley, and M. R. Palmer, Rare earth element speciation in geothermal fluids from Yellowstone National Park, Wyoming, USA, Geochim. Cosmochim. Acta, 62, 657–663, 1998.
Machida, H. and F. Arai, Akahoya Ash—A holocene widespread tephra erupted from the Kikai Caldera, South Kyushu, Japan, Quaternary Research, 17, 143–163, 1978 (in Japanese with English abstract).
Matsubaya, O., A. Ueda, M. Kusakabe, Y. Matsuhisa, H. Sakai, and A. Sasaki, An isotopic study of the volcanoes and the hot springs in Satsuma Iwo-jima and some areas in Kyushu, Bull. Geological Survey of Japan, 26, 375–392, 1975 (in Japanese with English abstract).
Matsumoto, T., Submarine eruptions on the Iwo-ga-Shima and the geology of the island and its surroundings, Bull. Volcanol. Soc. Japan, 3, 144–162, 1937 (in Japanese).
Matsuo, S., T. Suzuki, M. Kusakabe, H. Wada, and M. Suzuki, Isotopic and chemical composition of volcanic gases from Satsuma-Iwojima, Japan, Geochemical J., 8, 165–173, 1974.
Nogami, K., M. Yoshida, and J. Ossaka, Chemical composition of discolored seawater around Satsuma-Iwojima, Kagoshima, Japan, Bull. Volcanol. Soc. Japan, 38, 71–77, 1993.
Notsu, K., K. Ono, and T. Soya, Strontium isotopic relations of bimodal volcanic rocks at Kikai volcano in Ryukyu arc, Japan, Geology, 15, 345–348, 1987.
Ono, K., T. Soya, and T. Hosono, Geology of Satsuma-Io-jima district, quadrangle series, scale 1:50000, Tanegashima (16) No. 2, Geological Survey of Japan, 80 p, 1982 (in Japanese with English abstract).
Saito, E., Topographical map around Mt. Iwodake volcano, Open file report of Geological Survey of Japan, 308, 1998 (in Japanese).
Shimoike, Y., K. Kazahaya, and H. Shinohara, Soil CO2 emission at Satsuma-Iwojima volcano, Japan, Program and abstracts, The Volcanological Society of Japan, 2000, 2, 134, 2000 (in Japanese).
Shinohara, H., W. F. Giggenbach, K. Kazahaya, and J. W. Hedenquist, Geochemistry of volcanic gases and hot springs of Satsuma-Iwojima, Japan: Following Matsuo, Geochemical J., 27, 271–285, 1993.
Shinohara, H., K. Kazahaya, N. Matsushima, Y. Nishi, G. Saito, and Y. Kawanabe, Recent volcanic activity at the summit of Iwodake, Satsuma-Iwojima until November 1998, Report of Coordinating Committee for Prediction of Volcanic Eruption, 73, 104–105, 1999 (in Japanese).
Ueda, A. and T. Itaya, Microphenocrystic pyrrhotite from dacite rocks of Satsuma-Iwojima, southwest Kyushu, Japan and Solubility of Sulfur in Dacite Magma, Contrib. Mineral Petrol., 78, 21–26, 1981.
Vennemann, T. W., J. L. Muntean, S. E. Kesler, J. R. O’Neil, J. W. Valley, and N. Russell, Stable isotope evidence for magmatic fluids in the Pueblo Viejo epithermal acid sulfate Au-Ag deposit, Dominican Republic, Economic Geology, 88, 55–71, 1993.
Wood, S. A., The aqueous geochemistry of the rare-earth elements and yttrium: 2 Theoretical predictions of speciation in hydrothermal solutions to 350°C at saturation water vapor pressure, Chemical Geology, 88, 99–125, 1990.
Yoshida, M., T. Ozawa, and J. Ossaka, Molybdenum minerals—molybdenum blue and molybdenite—formed as volcanic sublimates at Satsuma-Iwo-jima volcano, Jour. Chem. Soc. Japan, 1972, 575–583, 1972 (in Japanese with English abstract).
Yoshida, T., K. Higuchi, and K. Yuhara, Alteration of rocks by geothermal activities in Satsuma Iwo-jima Island, Kagoshima Prefecture, Japan, Chinetsu, 13, 9–19, 1976 (in Japanese with English abstract).
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Hamasaki, S. Volcanic-related alteration and geochemistry of Iwodake volcano, Satsuma-Iwojima, Kyushu, SW Japan. Earth Planet Sp 54, 217–229 (2002). https://doi.org/10.1186/BF03353021
- Altered Rock
- Summit Crater
- Native Sulfur