R8: 変成岩とテクトニクス

[R8-06] Temperature reconstructions of rocks deformed at shallow crustal depths: implications of calcite thermometry from MBT and NT rocks of Himachal Himalayas

*Dyuti Prakash Sarkar¹, Jun-ichi Ando¹, Akihiro Kano³, Hirokazu Kato³, Gautam Ghosh², Kaushik Das¹ (1. Hiroshima Univ., 2. Presidency Univ., 3. Tokyo Univ.)

キーワード：Calcite twinning, Clumped isotope thermometry, MBT, NT

Estimating temperature and depth of formation of fault rocks is essential to elucidate fault zone processes. Current study focusses on temperature estimation of carbonate bearing shallow crustal fault rocks of the Himalayan frontal wedge bounded by MBT in the north and MFT in the south. Temperatures were estimated using the standard calcite twin morphology and clumped isotope thermometry. Significant temperature difference from Nahan Thrust of MFT (170±10℃) and MBT (262±30℃) suggest a depth difference of ~4km, considering standard continental geothermal gradient of 25℃/km.