Origin of natural sulfur-metal chimney in the Tangyin hydrothermal field,Okinawa Trough:constraints from rare earth element and sulfur isotopic compositions  

作　　者：Hong Cao Zhi-lei Sun Chang-ling Liu En-tao Liu Xue-jun Jiang Wei Huang 

机构地区：[1]The Key Laboratory of Gas Hydrate,Ministry of Land and Resources,Qingdao Institute of Marine Geology,Qingdao 266071,China [2]Laboratory for Marine Mineral Resources,Qingdao National Laboratory for Manne Science and Technology,Qingdao 266071,China [3]College of Marine Science and Technology,China University ofGeosciences (Wuhan),Wuhan 430074,China

出　　处：《China Geology》2018年第2期225-235,共11页中国地质（英文）

基　　金：the Natural Science Foundation of China (41606086);the Taishan scholar Special Experts Project (ts201712079);the National Key Research and Development Program (2017YFC0307704);the Marine Geological Survey project of China Geological Survey (DD20160218, DD20160344).

摘　　要：For the first time,we present the rare earth element (REE)and sulfur isotopic composition of hydrothermal precipitates recovered from the Tangyin hydrothermal field (THF),Okinawa Trough at a water depth of 1206 m.The natural sulfur samples exhibit the lowest ∑REE concentrations (∑REE= 0.65×10^-6-4.580×10^-6)followed by metal sulfides (∑REE=1.71×10^-6-11.63×10^-6).By contrast,the natural sulfur-sediment samples have maximum ∑REE concentrations (∑REE=1 1.54×10^-6-33.06×10^-6), significantly lower than those of the volcanic and sediment samples.Nevertheless,the δEu,δCe,(La/Yb)N, La/Sm,(Gd/Yb)N and normalized patterns of the natural sulfur and metal sulfide show the most similarity to the sediment.Most hydrothermal precipitate samples are characterized by enrichments of LREE (LREE/HREE=10.09-24.53)arid slightly negative Eu anomalies or no anomaly (δEu=0.48-0.99),which are different from the hydrothermal fluid from sediment-free mid-oceanic ridges and back-are basins,but identical to the sulfides from the Jade hydrothermal field.The lower temperature and more oxidizing conditions produced by the mixing between seawater and hydrothermal fluids further attenuate the leaching ability of hydrothermal fluid,inducing lower REE concentrations for natural sulfur compared with metal sulfide;meanwhile,the negative Eu anomaly is also weakened or almost absent.The sulfur isotopic compositions of the natural sulfur (δ^34S=3.20‰-5.01‰,mean 4.23 ‰)and metal sulfide samples (δ34S=0.82‰-0.89‰,mean 0.85‰)reveal that the sulfur of the chimney is sourced from magmatic degassing.

关 键 词：Hydrothormal processes NATURAL SULFUR ISOTOPIC compositions REE Tangyin field OKINAWA TROUGH China 

分 类 号：P[天文地球]