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Presents a study which emphasized the need for the elastic model applied by researchers to explain the preservation of the coesite inclusions in rigid host minerals. Interpretation of polycrystalline quartz inclusions; Implication of the varying degrees of coesite-quartz transition in coesite inclusions in zircon; Fluid activity required in the preservation of coesite in fractured garnet.

Examines the mineral inclusions in zircon from gneisses in the ultrahigh-pressure (UHP) zone of the Dabie Mountains in China using laser Raman spectrophotometry. Significance of the occurrence of barite and anhydrite; Implications as to the origin of eclogitic blocks; Zircon growth history and interpretation of zircon ages.

The discovery of coesite in metasedimentary rocks not only implies that the materials of continental crust with low density could subduct down to mantle depth, but also initiates a series of studies on continent-deep-subduction. Could continental crust be subducted down to the depth of note than 300 km? Water played a role in ultrahigh-pressure (UHP) metamorphism although limited. Was the fluid really limited within motor-scale, or the authors suggested, at mantle depth? Erosion and extension could remove the overburden of the UHO rocks, while squeezing and buoyancy could lift up the UHP rocks through the overburden. What, however, is the main process and mechanism with which the UHP rocks have exhumed from mantle depth? all progress of these studies will eventually form and complete a new paradigm of geodynamics. [ABSTRACT FROM AUTHOR]

Discusses the results of studies of the Dabie-Sulu UHP rocks belt from 1994 to 1999. Information on UHP metamorphism; How deeply could the continental crust subduct; Role of fluid in UHP metamorphism.