摘要
Hydrothermal chimney is a product of hydrothermal activity on the seabed. Chimney sam-ples of Jade hydrothermal area were dredged from Izena depression of the Okinawa Trough,are char-acterized with relatively enriched light rare earth elements (LREE) and high-positive Eu anoma-lies.87Sr/86Sr and 143Nd/144Nd of these samples are exactly located between the values of seawater andacidic pumice,averaged at 0.708928 and 0.512292,respectively.These characteristics imply thatthe main source of hydrothermal sulfide at Jade area is possibly the undersurface acidic rocks.Themineralizing mechanism can be summarized as follows:Large amount of mineralized material would beleached out and LREE-enriched hydrothermal solution would be subsequently produced as a result ofthermo-chemical exchange reaction between acidic volcanic rocks and heated seawater that penetra-ted in advance from upper water mass.The spurting out from the seabed and quickly crystallizing inthe seawater of hydrothermal solution are responsible for the formation of Cu-Zn sulfide and barite-amorphous SiO2 minerals that are characterized with enriched LREE and positively strong Eu anoma-lies.