Elucidation of physicochemical conditions of serpentinization in subduction zone

2016 Fiscal Year Final Research Report

• Project/Area Number: 25400520
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Petrology/Mineralogy/Economic geology
• Research Institution: Osaka Prefecture University
• Principal Investigator: MAEKAWA Hirokazu 大阪府立大学, 理学(系)研究科(研究院), 教授 (50173696)
• Project Period (FY): 2013-04-01 – 2017-03-31
• Keywords: 蛇紋岩 / 蛇紋岩化作用 / 変成岩 / 藍閃石片岩相 / エクロジャイト相 / マリアナ

Outline of Final Research Achievements

In the Mariana forearc, there are many serpentinite seamounts composed of serpentinized peridotites derived from the wedge mantle. The serpentine mineral was initially the low-temperature phase, i.e., lizardite / chrysotile. It secondarily changed into the high-temperature phase, i.e., antigorite, which commonly coexists with Fe-rich olivine and diopside, and finally, it again changed into the low-temperature phase. On the other hand, the mafic rocks which occur as xenoliths in the seamounts were metamorphosed under the eclogite facies condition, and thereafter, they were retrogressively metamorphosed under the low temperature glaucophane schist facies condition. The thermal histories of both rock types are thought to be consistent. It probably reflects the flow of rocks within the subduction zone.

Free Research Field

変成岩岩石学