REE and Sr-Nd isotope characteristics of hydrothermal chimney at Jade area in the Okinawa Trough

作     者：LIUYanguang MENGXianwei FUYunxia LIU Yanguang, MENG Xianwei, FU Yunxia Key Laboratory of Marine Sedimentology and Environment Geology of State Oceanic Administration, Qingdao 266061,China First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China The College of Marine Geosciences, Ocean University of China, Qingdao 266003, China Geological Resource and Geotechnical Engineering Cooperation of Qingdao, Qingdao 266071, China

作者机构：KeyLaboratoryofMarineSedimentologyandEnvironmentGeologyofStateOceanicAdministrationQingdao266061China GeologicalResourceandGeotechnicalEngineeringCooperationofQingdaoQingdao266071China 

出 版 物：《Acta Oceanologica Sinica》 (海洋学报（英文版）)

年 卷 期：2004年第23卷第2期

页      面：287-296页

核心收录：

学科分类：070702[理学-海洋化学] 07[理学] 0707[理学-海洋科学] 

基　　金：This study was supported by the National Natural Science Foundation of China under the contract No.40276024 and 49873015 

主　　题：hydrothermal chimney rare earth elements Sr and Nd isotopes 

摘      要：Hydrothermal chimney is a product of hydrothermal activity on the seabed. Chimney samples dredged from Jade hydrothermal area in Izena depression of the Okinawa Trough, are characterized by relatively enriched light rare earth elements (LREE) and strongly positive Eu anomalies. 87Sr/86Sr and 143Nd/144Nd of these samples are exactly between those of seawater and of acidic pumice, averaged at 0.708928 and 0.512292, respectively. These characteristics imply that the main source of hydrothermal sulfide at Jade area is possibly the undersurface acidic rocks. The mineralizing mechanism can be summarized as follows: Large amount of mineralized material would be leached out and LREE-enriched hydrothermal solution would be subsequently produced as a result of thermo-chemical exchange reaction between acidic volcanic rocks and heated seawater that penetrated in advance from upper water mass. The spurting out from the seabed and quickly crystallizing in the seawater of hydrothermal solution are responsible for the formation of Cu-Zn sulfide and barite-amorphous SiO2 minerals that are characterized by enriched LREE and positively strong Eu anomalies.