論文

査読有り 筆頭著者
2017年7月

Cooling and crystallization of rhyolite-obsidian lava: Insights from micron-scale projections on plagioclase microlites

JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
  • Kyohei Sano
  • ,
  • Atsushi Toramaru

341
開始ページ
158
終了ページ
171
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1016/j.jvolgeores.2017.05.012
出版者・発行元
ELSEVIER SCIENCE BV

To reveal the cooling process of a rhyolite-obsidian flow, we studied the morphology of plagioclase microlites in the Tokachi-Ishizawa lava of Shirataki, northern Hokkaido, Japan, where the structure of the lava can be observed from obsidian at the base of the flow to the innermost rhyolite. Needle-like micron-scale textures, known as "projections", occur on the short side surfaces of the plagioclase microlites. Using FE-SEM we discovered a positive correlation between the lengths and spacings of these projections. On the basis of the instability theory of an interface between melt and crystal, and to understand the length and spacing data, we developed a model that explains the positive correlation and allows us to simultaneously estimate growth rates and growth times. Applying the model to our morphological data and the estimated growth rates and growth times, we suggest that the characteristics of the projections reflect the degree of undercooling, which in turn correlates with lava structure (the obsidian at the margin of the flow experienced a higher degree of undercooling than the interior rhyolite). The newly developed method provides insights into the degree of undercooling during the final stages of crystallization of a rhyolitic lava flow. (C) 2017 Elsevier B.V. All rights reserved.

Web of Science ® 被引用回数 : 5

リンク情報
DOI
https://doi.org/10.1016/j.jvolgeores.2017.05.012
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000406728200014&DestApp=WOS_CPL

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