Thermal structure in subducted units from continental Moho depths in a palaeo subduction zone, the Asemigawa region of the Sanbagawa metamorphic belt, SW Japan

Yui Kouketsu*, Kazushi Sadamoto, Hayato Umeda, Hirokazu Kawahara, Takayoshi Nagaya, Tomoki Taguchi, Hiroshi Mori, Simon Wallis, Masaki Enami

*この研究の対応する著者

研究成果: Article査読

抄録

Raman CM geothermometry applied to 126 samples of pelitic schists collected over an area of 11 km × 7 km reveals the thermal structure of the Asemigawa region of the Sanbagawa metamorphic belt, southwest Japan in unprecedented detail. In general, the estimated temperatures gradually increase from south to north in the range of 288–553°C. However, a temperature gap from ~380 to ~440°C is identified near the boundary between the chlorite and garnet zones. This temperature region matches the depth of the continental Moho of the Sanbagawa subduction zone. The temperature gradient in the higher-temperature domain is higher than that in the lower-temperature domain, and large-scale tight folds that affect the thermal structure are developed in the high-grade units and in the vicinity of the temperature discontinuity. These geological structures probably reflect that the exhumed slab units was dammed at the Moho depth due to the upward movement being impeded by increase in the coupling strength of the overlying rocks associated with exhumation from beneath serpentinite rocks to a shallower domain overlain by crustal rocks. Changes in the coupling strength along the subduction boundary led the strong folding at the higher-temperature domain and the pre-formed foliation developed at the Moho depth may have acted as the tectonic boundary, resulting in a temperature discontinuity. These results will contribute to elucidating various geological phenomena occurring in the forearc regions of modern subduction zones.

本文言語English
ページ(範囲)727-749
ページ数23
ジャーナルJournal of Metamorphic Geology
39
6
DOI
出版ステータスPublished - 2021 8
外部発表はい

ASJC Scopus subject areas

  • 地質学
  • 地球化学および岩石学

フィンガープリント

「Thermal structure in subducted units from continental Moho depths in a palaeo subduction zone, the Asemigawa region of the Sanbagawa metamorphic belt, SW Japan」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

引用スタイル