The U-Th-40 K concentrations of granite are on 1-2 orders of magnitude greater than those of basaltic-ultrabasic rocks. Radiogenic heat of a granitic melt has significant influence on the cooling-crystallization period of the melt. In this paper we derived a formula to calculate prolongation period (t A ) of cooling-crystallization of a granitic melt caused by radiogenic heat. Calculation using this formula and radioactive element concentrations (U=5.31×10 −6 ; Th=23.1×10 −6 ; K=4.55%) for the biotite adamellite of the Jinjiling batholith shows that the t A of the adamellite is 1.4 times of the cooling period of the granitic melt without considering radiogenic heat from the initial temperature (T m =960℃) to crystallization temperature (T c =600℃) of the melt. It has been demonstrated that the radiogenic heat produced in a granitic melt is a key factor influencing the cooling-crystallization process of the granitic melt, and is likely one of the reasons for inconsistence between emplacement ages and crystallization ages of many Meso-Cenozoic granitoids.

Based on the theory of thermal conductivity, in this paper we derived a formula to estimate the prolongation period ( d t~) of cooling-crystallization process of a granitic melt caused by latent heat of crystallization as follows:where TM is initial temperature of the granite melt, TC crystallization temperature of the granite melt, C p specific heat, dtd cooling period of a granite melt from its initial temperature ( T~I ) to its crystallization temperature (Tc), QL latent heat of the granite melt.The cooling period of the melt for the Fanshan granodiorite from its initial temperature (900°C) to crystallization temperature (600°C) could be estimated -210,000 years if latent heat was not considered. Calculation for the Fanshan melt using the above formula yields a At,, value of -190,000 years, which implies that the actual cooling period within the temperature range of 900"-600"C should be 400,000 years. This demonstrates that the latent heat produced from crystallization of the granitic melt is a key factor influencing the cooling-crystallization process of a granitic melt, prolongating the period of crystallization and resulting in the large emplacement-crystallization time difference (ECTD) in granite batholith.

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The 834S values of pyrite from the ores and host carbonate range from 1.0 to -39.8%o and from 8.2 to -38.1 %o, respectively. Depletion in 34S and a wide range of the 634S values for sulfide indicate that the sulfur in both the ores and host carbonates is biogenic. The S13C values of calcite from the ores range from 2.9 to -4.4%0, which are similar to those of the host carbonate, ranging from 3.3 to -1.8. The majority of S13C and 6180 values of carbonate from the deposits lie within the range for carbon and oxygen isotope compositions that exist in marine sedimentary carbonate. The similarity between the sulfur and carbon isotope compositions of the ores and host carbonate indicates that the sulfur and carbon as well as metallic elements in the ores may have derived from the host marine sedimentary carbonate. The 6180 and sD values cf the mineralizing fluids range from 12.6 to -2.1%o and from -26.8 to -54.8%o, respectively. The oxygen and hydrogen isotope data demonstrate that the mineralizing fluids were derived from metamorphic water and were mixed with shallow groundwater. Such fluids may have been released by faulting and shearing, which also opened the channel ways for circulation of minerarizing fluids and facilitated their mingling with meteoric water.

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