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

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• 作者：Liu Yanguang(刘焱光)；Meng Xianwei(孟宪伟)；Fu Yunxia(付云霞)
• 单位1：Key Laboratory of Marine Sedimentology and Environmental Geology,First Institute of Oceanography,State Oceanic Administration
• 单位2：Geoscience Institute,Oceanographic University of China,Qingdao
• 语种：中文
• 作者关键词：Hydrothermal chimney；rare earth elements；Sr and Nd isotopes
• 起始页：370
• 总页数：9
• 经费资助：Supported by the National Science Foundation of China(NSFC):40276064,49873015.
• 刊名：海注沉积与环境地质国家海洋局重点实验室研究年报
• 是否内版：否
• 主编：石学法；孟宪伟；刘保华
• 期刊索取号：P371.0691672003-2004

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.