大别山超高压变质岩后成合晶矿物中微细流体包裹体的透射电镜研究

The research about fluid inclusions has significant implications for understanding the formation condition, tectonic evolution and dynamic process of crustal rocks. Fluid inclusions at a nano-scale to submicron-scale and their relationship with structural defect in retrograde metamorphic minerals or symplectitic corona minerals (albite, augite-aegirine, taramite and magnetite) from UHP jadeite quartzite at Shuanghe of Dabie Mountains, China, have been investigated by using transmission electron microscopy (TEM). It has been observed that the size (1 nm ∼ 200 nm) of fluid inclusions in such minerals is much smaller than that (10 nm ∼ 350 nm) in quartz. Most fluid inclusions are rounded or negative crystal shaped, while some being irregular orgrouped, with H₂O or CO₂, fluids. The fluid inclusions often intergrow in dislocations, dislocation networks, crystal boundary or subboundaries and so on. These dislocations and structural defect space represent a favorable path for non-crepitative fluid phase leakage. The cluster of water molecules on the nano-scale (1 nm ∼ 30 nm) with non-uniform distribution has been discovered in deformed albite. The cluster of water molecules presenting in spherical inclusions in symplectitic minerals directly causes hydrolytic weakening and induces the plastic deformation of symplectitic minerals by dislocations. These fluids and cluster of water molecules could accelerate the plastic deformation and the retrograde metamorphism course of rocks, which reflecting an uplift history after high-pressure (HP) metamorphism at Dabie Mountains.