Abstract:

In the past two decades, the study of ultra-high pressure metamorphism has been greatly advanced. The  mineralogical criteria for the ultra-high  pressure metamorphism have been increased far more than  coesite alone. There are even more new mineralogical criteria of UHP metamorphism to be discovered  in the combination with the new results of experimental mineralogy. The criteria hitherto recognized are of 3 categories:(1)ultrahigh pressure  polymorphism  of minerals, such as,  coesite and diamond ;(2) the exsolution of ultra-high pressure minerals, such as, K-clinopyroxene,  majoriticpyrope, highsilica sphene, and (3)ultrahigh pressure minerals  and mineral association,such as,  phengite,aragonite, magnesite etc. The present paper deals with the geological and mineralogical characteristics of these criteria and the perspective of their application.

Key words: polymorphism, pseudomorphism, exsolution, ultra-high pressure metamorphism, collisional orogenic belt, Dabie-Sulu orogenic belt