The thermal structure of continental crust in active orogens: insight from Miocene eclogite and granulite xenoliths of the Pamir Mountains

Rare Miocene eclogite and granulite xenoliths from the Tajik National Park (Pamirs) reveal that crustal material subducted beneath Earth's largest collisional orogen reached ultrahigh-temperature–(near)ultrahigh-pressure conditions, with temperatures exceeding 1000 °C at depths of up to 33 kbar. These findings suggest an average thermal gradient of ∼12–13 °C km⁻¹, indicating that the rocks were introduced to mantle depths via subduction or gravitational foundering rather than post-thermal relaxation. The study combines oxygen-isotope thermometry, major-element thermobarometry, and pseudosection analysis to reconstruct the thermal structure of continental crust in active orogens.

GORDON, S. M., LUFFI, P., HACKER, B., VALLEY, J., SPICUZZA, M., KOZDON, R., KELEMEN, P., RATSHBACHER, L., & MINAEV, V. (2012). The thermal structure of continental crust in active orogens: insight from Miocene eclogite and granulite xenoliths of the Pamir Mountains. Journal of Metamorphic Geology, 30(4), 413–434. Portico. https://doi.org/10.1111/j.1525-1314.2012.00973.x