Nature of accretion related to Paleo-Tethys subduction recorded in northern Thailand: Constraints from mélange kinematics and illite crystallinity
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- 作者：Hidetoshi Hara ; Koji Wakita ; Katsumi Ueno ; Yoshihito Kamata ; Ken-ichiro Hisada ; Punya Charusiri ; Thasinee Charoentitirat ; Pol Chaodumrong
- 关键词：Accretionary complex ; Shear deformation ; Low-grade metamorphism ; Paleo-Tethys ; Subduction zone ; Inthanon zone
- 刊名：Gondwana Research
- 出版年：2009
- 出版时间：October 2009
- 年：2009
- 卷：16
- 期：2
- 页码：310-320
- 全文大小：3743 K
文摘
We reconstructed the accretion process related to Paleo-Tethys subduction recorded in northern Thailand, based on mélange and thrust structures, and metamorphic temperatures derived from illite crystallinity data. Mélange formation was characterized by hydrofracturing and cataclastic deformation, with mud injection under semi-lithified conditions followed by shear deformation and pressure solution. Illite crystallinity data suggest metamorphic temperatures below 250 °C during mélange formation. The combined structural and metamorphic data indicate that during mélange formation, the accretionary complex related to Paleo-Tethys subduction developed at shallow levels within an accretionary prism. Asymmetric shear fabrics in mélange indicate top-to-south shear. After correction for rotation associated with collision between the Indian and Eurasian continents, the trend of the Paleo-Tethys subduction zone is estimated to have been N80 °E. We conclude that the Paleo-Tethys was subducted northward beneath the Indochina Block from the Permian to Triassic.