Abstract:

 Characteristics, formation and migration of the particles carried by ascending gas flow in the concealed metal deposits were studied. In the research, the theory and method of geochemistry and of nano scale science and technology were  adopted and more than ten metal deposits had been studied. The results showed that particles carried by ascending gas flow in surface sediments above concealed metal orebodies occur in forms of individual particles and particle aggregations. The shapes of individual particles are spherical, nearspherical, irregular, regular polygon, and long columnar. The particles are crystalline, amorphous, or partly ordered semicrystalline. The shapes of aggregations are irregular, spherical, or nearspherical. Their mineral compositions are dominantly native gold, native copper, chloride, oxide, sulfate, and hydroxide. The oreforming elements such as Au, Cu may be in the form of native metals or native alloys. The oreforming elements such as Cu, Pb, Zn may be in the form of oxide, or sulfate. They, too, may be the impurity elements existing in particles such as chloride, oxide, sulfate, and hydroxide. The particles are the indicators of concealed metal orebodies. After mineralization, the particles related to the concealed metal orebodies were mainly formed by faulting, oxidation and biological effects. In the ascending gas flow, particles are in Brownian motion.

Key words: concealed orebodies； particles； particle aggregation, metallic element migration, Brownian motion