Joint research project of the Department Geology and Mineralogy of the RMCA and of the United Institute of Geology, Geophysics and Mineralogy of Novosibirsk, Siberian Branch of the Russian Academy of Sciences. Mechanisms and processes associated with the fast exhumation of HP/UHP metamorphic rocks from their deep (mantle)- to their mid-crustal level, are investigated. The combination and confrontation of mineralogical and structural analytical approaches on well outcropping sections (two different UHP levels in the Kokchetav, Kazakhstan and eclogite facies rocks from the Palaeoproterozoic Ubende belt, Tanzania) are explored to 1) provide information on the exhumation processes and mechanisms from unusual depths and 2) to constrain the early stage P-T evolutionary conditions of the Palaeoproterozoic Ubende shear belt.