Formation process and local structure of amorphous aluminosilicates in fault zone

2017 Fiscal Year Final Research Report

• Project/Area Number: 15H03746
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Petrology/Mineralogy/Economic geology
• Research Institution: Hokkaido University
• Principal Investigator: Kameda Jun 北海道大学, 理学研究院, 准教授 (40568713)
• Co-Investigator(Renkei-kenkyūsha): SUGIYAMA Kazumasa 東北大学, 金属材料研究所, 教授 (40196762) ; TSUTSUMI Akito 京都大学, 大学院理学研究院, 助教 (90324607) ; TAKESHITA Toru 北海道大学, 大学院理学研究院, 教授 (30216882)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 断層岩 / メカノケミストリー / 摩擦発熱 / 粘土鉱物

Outline of Final Research Achievements

Thermal and mechanical activations on hydrous clay minerals in fault zones are examined. High-temperature XRD experiments demonstrated that kaolinite and chlorite, typical clay components in crustal faults, dehydroxylate in a different manner, which can be utilized as a new temperature proxy for seismogenic faults in subduction zones. In addition, we showed that mechanical action can facilitate mineral dehydroxylation reaction due to selective degradation of clay interlayers connected by hydrogen bondings. We also investigated smectite/illite mixed layers around a slip zone of the mega-branching fault of the Nankai Trough, and showed that mechanochemical processes possibly associated with seismogenic faulting can activate its transfrormation reaction by reducing the activation energy of the reaction.

Free Research Field

構造地質学