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Discusses how the hydrotherman clay minerals that formed in the main metallogenic stage of the Changkeng disseminated-type gold deposit in central Guangdong were analyzed by a laser probe. Consideration of how the results give Ar-Ar isochron ages of 109.9 &plusmn, 1.4 to 110.1 &plusmn, and 1.3 Ma, which are 30 to 50 Ma older than the age of silver ore bodies in the deposit; How both gold and silver mineralizations were not related to hidden granite batholith in the mining district; Reference to how the study shows that the laser probe is a sound datin tool applicable to sediment-hosted disseminated-type gold deposit.

Presents a study which examined the effects of various organic acids on the dissolution of rare-earth elements from a sample of the weathering crust of granite in Gonghe, Guangdong, China. Review of related studies; Materials and methodology; Results and discussion.

Microbes were cultured and identified from the samples collected at various depths in 4 weathering profiles of REE-bearing granites in Gonghe, Guangdong. The microbes were found existing at the depth of 0 - 5 m in all the profiles. The main microbes include coccus (Staphylococcus, Streptococcus), bacillus (Bacillus, Clostridium and Escherichia Coli), actinomyces and fungi (Saccharomycete, Penicillium, Fusarium, Aspergillus Aiger and Mucor). The number of colonies decreases downwards in the profiles. Experimental studies show that all the microbes used in the experiment can accelerate downward migration of REE in the experimental tubes. The ability to accelerate the migration of REE decreases in a sequence of fungi→actinomyces→bacillus→coccus. The microbes can change the modes of occurrence of REE in the weathering crust. The coccus, bacillus and actinomyces can increase the amounts of REE in ion state, whereas the fungi have a stronger ability to form organic compounding REE and accumulate REE than the bacteria do. [ABSTRACT FROM AUTHOR]

Focuses on a study on the content and composition of light hydrocarbons in ore-forming fluids in minerals from the Changkeng gold-silver deposit in Guangdong, China and its constraints on ore genesis. Samples and analytical method; Analytical results and discussion; Conclusion.