Estimating subduction boundary stresses and incorporation in next-generation modeling

估计俯冲边界应力并纳入下一代建模

• 批准号: 21H01188
• 负责人: WALLIS R・Simon
• 金额: $ 10.82万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2021
• 资助国家: 日本
• 起止时间: 2021-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-21H01188/
• 关键词: 沈み込み; 応力; 石英; 微細組織; 圧力温度経路; Subduction; Stress; Sanbagawa metamorphism; Temperature; Thermal modeling; 三波川帯; EBSD; 沈み込み帯; 三波川変成作用; 石英粒径; EBSD測定; 温度圧力経路; 熱モデリング

The purpose of this research is to use the rock record in subduction-type metamorphic belts, and in particular the well-developed and studied Sanbagawa belt of south west Japan, to estimate the shear stress acting along the subduction interface and incorporate these results in new thermal models of subduction zones. An important part of this study relies on accurate determination of the metamorphic temperature. We have made signifiant progress with this issue. In particular, we have shown that conventional methods for estimating Fe(II)/(III) ratios in the higher grade metamorphic rocks of the Sanbagawa belt are in sufficient to give accurate temperature estimates based on Mg-Fe cation exchange thermometry. We carried out numerous experiments using synchrotron radiation-based Micro XANES methods supported by Moessbauer analyses. There are still several aspects of the method that need to be refined before reliable results can be obtained, but the results of the previous year show considerable promise in the possibility to obtain significantly improved temperature estimates in some high-grade samples. We have also made significant progress in the analyses of microstructures required to derive reliable stress estimates. The progress includes evaluating the sectioning effect in measurements of grain size; something which is not incorporated in most previous studies. We also explored the theoretical background for approaches to use measurements of natural samples deformed under plane stress to laboratory examples deformed under uniaxial shortening.

这项研究的目的是利用俯冲型变质带中的岩石记录，特别是日本西南部发育和研究得很好的三叶川带，估计沿俯冲界面作用的剪应力，并将这些结果纳入新的俯冲带热模型。这项研究的一个重要部分是依赖于变质温度的准确测定。我们在这个问题上取得了重大进展。特别是用常规方法估算桑巴加瓦带高级变质岩中Fe(II)/(III)的比值，足以给出基于镁铁阳离子交换测温法的准确温度估算。我们使用基于同步辐射的Micro XANES方法进行了大量的实验，并得到了Moessbauer分析的支持。在获得可靠的结果之前，该方法仍有几个方面需要改进，但前一年的结果显示，在一些高级样品中获得显著改进的温度估计的可能性相当大。我们还在得出可靠的应力估计所需的微观结构分析方面取得了重大进展。这一进展包括在测量颗粒大小时评估切片效应；这一点在以前的大多数研究中都没有包括在内。我们还探讨了将平面应力下变形的自然样品的测量方法应用于单轴缩短变形的实验室样品的理论背景。

项目成果

Microstructures and deformation temperature of carbonate mylonites in Shajigami shear zone at eastern margin of Abukuma Mountains, Northeastern Japan

日本东北部阿武隈山脉东缘沙治上剪切带碳酸盐糜棱岩显微结构及变形温度

• 发表时间: 2021
• 作者: Hiroaki Yokoyama;Jun Muto;Hiroyuki Nagahama
• 通讯作者: Hiroyuki Nagahama

Recognition of broad thermal anomaly around the median tectonic line in central Kii peninsula, southwest Japan: Possible heat sources

日本西南部纪伊半岛中部中位构造线周围存在广泛的热异常：可能的热源

• DOI: 10.1111/iar.12440
• 发表时间: 2022
• 期刊: Island Arc
• 影响因子: 1.5
• 作者: Ken Yamaoka;Simon Wallis
• 通讯作者: Simon Wallis

Use of contact metamorphic aureoles to estimate magma flux rates

使用接触变质光环来估计岩浆通量率

• 发表时间: 2022
• 作者: Simon Richard Wallis;Ken Yamaoka;Catherine Annen;Akira Miyake
• 通讯作者: Akira Miyake

Quantitative Evaluation of Water Flux in the Franciscan Subduction Zone Based on Volume Change of Metamorphic Rocks

基于变质岩体积变化的方济各俯冲带水通量定量评价

• 发表时间: 2022
• 作者: Shogo Soejima;Simon Richard Wallis
• 通讯作者: Simon Richard Wallis

Evidence for suboceanic small-scale convection from a “garnet”-bearing lherzolite xenolith, Aitutaki Island, Cook Islands

库克群岛艾图塔基岛含“石榴石”的二辉橄榄岩捕虏体存在海底小规模对流的证据

• 发表时间: 2022
• 作者: Norikatsu Akizawa;Kazuhito Ozawa;Tetsu Kogiso;Akira Ishikawa;Simon Richard Wallis;Tatsuhiko Kawamoto;Akihiro Tamura;Tomoaki Morishita
• 通讯作者: Tomoaki Morishita