西南印度洋中脊热液产物稀土元素组成变化及其来源

李小虎; 初凤友; 张平萍; 雷吉江; 余星; 赵宏樵

西南印度洋中脊热液产物稀土元素组成变化及其来源

国家海洋局海底科学重点实验室, 浙江杭州 310012;国家海洋局第二海洋研究所, 浙江杭州 310012

基金项目: 国家自然科学基金项目（40906036，41276055）；大洋矿产资源研究协会“十二五”专项项目（DY125-12-R-02，04，06，DY125-11-R-06）；海洋公益性行业科研专项（201005003）。

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- 收稿日期: 2013-06-05

Characteristics of composition and source of rare earth elements in the seafloor hydrothermal products from the Southwest Indian Ridge

Key Laboratory of Submarine Geoscience of State Oceanic Administration, Hangzhou 310012, China;Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China

摘要

摘要: 对西南印度洋中脊热液区不同热液产物稀土元素（REE）进行了分析，探讨了热液产物形成过程中稀土元素组成变化及其来源。研究结果表明：不同热液产物稀土元素总量变化范围从3.47°10^-7到4.80°10^-5，轻重稀土比值（LREE/HREE）从2.06到6.16，表明轻重稀土有较大程度分异，δEu异常（δEu=0.86~3.88）和δCe异常（δCe=0.40~0.86）显示热液产物中REE呈Eu富集和Ce亏损特征。稀土元素球粒陨石标准化模式呈现两种类型：（1）呈轻微富集LREE的平坦模式，∑REE大于2°10^-5；（2）呈显著富集LREE和正Eu异常模式，∑REE小于5°10^-7。模式1类似于洋壳火山岩REE配分模式，而模式2与西南印度洋中脊黑烟囱REE模式相似，也与典型洋中脊热液喷口流体和硫化物LREE富集和正Eu异常模式类似。热液产物中稀土元素含量变化和模式特征以及Mg与LREE极强正相关关系可能反映了西南印度洋中脊硫化物形成在热液流体与海水混合沉淀的初始阶段，后期经历了广泛的热液流体再循环和海水蚀变过程。
- 稀土元素 /
- 热液产物 /
- 源区 /
- 热液流体 /
- 西南印度洋中脊
Abstract: Rare earth element (REE) measurements were carried out on samples from the Southwest Indian Ridge. The results show that the variation range of ∑REE is from 3.47°10^-7 to 4.80°10^-5 with three orders of magnitude which are similar to the difference of ∑REE content between hydrothermal fluid and seawater. The ratio of LREE/HREE (from 2.06 to 6.16),δEu value (δEu:0.86 to 3.88) and δCe value (δCe:0.40 to 0.86) of the hydrothermal products indicate that there are significant differentiation between LREE and HREE,and REE patterns with middle positive Eu abnormal and negative Ce abnormal. There are two different characteristics of REE pattern with chondrite normalization: (1) ∑REE is more than 2°10^-5,which shows slightly enrich LREE with relatively flat pattern; (2) ∑REE is less than 5°10^-7,which shows significantly enrich LREE with middle positive Eu abnormal pattern. The former pattern is similar to the REE pattern of volcanic rock from the oceanic crust. The latter pattern is similar to REE pattern of black smoker from the Southwest Indian Ridge,which is also similar to REE pattern with LREE enrichment and positive Eu abnormal pattern of the typical hydrothermal fluid and sulfide from mid-ocean ridge. The results of REE composition and REE pattern,as well as the strong positive relationship among Mg concentration and LREE concentration,suggest that the hydrothermal products affected extensively by the recycling of hydrothermal fluid and alteration of seawater,although sulfide precipitating at the initial phase of mixing between hydrothermal fluid and seawater in the Southwest Indian Ridge.
- rare earth element (REE) /
- hydrothermal products /
- source /
- hydrothermal fluid /
- Southwest Indian Ridge

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参考文献(36)

Klinkhammer G P,Elderfield H,Edmond J M,et al. Geochemical implications of rare earth element patterns in hydrothermal fluids from mid-ocean ridges[J]. Geochimica et Cosmochimica Acta,1994,58: 5105-5113.

Mitra A,Elderfield H,Greaves M J. Rare earth elements in submarine hydrothermal fluids and plumes from the Mid-Atlantic Ridge[J]. Marine Chemistry,1994,47: 217-236.

James R H,Elderfield H,Palmer M R. The chemistry of hydrothermal fluids from the Broken Spur site,29°N Mid-Atlantic Ridge[J]. Geochimica et Cosmochimica Acta,1995,59(4): 651-659.

Michard A,Albaréde F,Michard G,et al. Rare earth elements and uranium in high-temperature solutions from East Pacific Rise hydrothermal vent field (13°N)[J]. Nature,1983,303: 795-797.

Michard A,Albaréde F. The REE content of some hydrothermal fluids[J]. Chemical Geology,1986,55: 51-60.

Tao C,Wu G,Ni J,et al. New hydrothermal fields found along the Southwest Indian Ridge during the Legs 5-7 of the Chinese DY115-20 expedition. Eos (Transactions,American Geophysical Union),Fall Meeting supplement,2009,OS21A-1150.

Tao Chunhui,Jian Lin,Shiqin Guo,et al. First active hydrothermal vents on an ultraslow-spreading center: Southwest Indian Ridge[J]. Geology,2012,40(1): 47-50.

Tao C,Li H M,Huang W,et al. Mineralogical and geochemical features of sulfide chimney from the 49°39'E hydrothermal field on the Southwest Indian Ridge and their geological significance[J]. Chinese Science Bulletin,2011,56: 2828-2838.

Cao Zhimin,Cao Hong,Tao Chunhui,et al. Rare earth element geochemistry of hydrothermal deposits from Southwest Indian Ridge[J]. Acta Oceanologica Sinica,2012,31(2): 62-69.

Bau M. Rare-earth element mobility during hydrothermal and metamorphic fluid-rock interaction and the significance of the oxidation state of europium[J]. Chemical Geology,1991,93: 219-230.

Wood S A, Williams-Jones A E. The aqueous geochemistry of the rare-earth elements and yttrium 4.Monacite solubility and REE mobility in exhalative massive sulfide-depositing environments[J]. Chemical Geology,1994,115: 47-60.

Haas J R,Shock E L,Sassini D C. Rare earth elements in hydrothermal systems: estimates of standard partial molal thermodynamic properties of aqueous complexes of the rare earth elements at high pressures and temperatures[J]. Geochimica et Cosmochimica Acta,1995,59(21): 4329-4350.

Bach W,Roberts S,Vanko D A,et al. Controls of fluid chemistry and complexation on rare-earth element contents of anhydrite from the Pacmanus subseafloor hydrothermal system,Manus Basin,Papua New Guinea[J]. Mineralium Deposita,2003,38(8): 916-935.

Coppin F,Berger G,Bauer A,et al. Sorption of lanthanides on smectite and kaolinite[J]. Chemical Geology,2002,182: 57-68.

Yang K,Scott S D. Possible contribution of a metal-rich magmatic fluid to a sea-floor hydrothermal system[J].Nature,1996,383: 420-423.

Douville E,Bienvenu P,Charlou J L,et al. Yttrium and rare earth elements in fluids from various deep-sea hydrothermal systems[J].Geochimica et Cosmochimica Acta,1999,63: 627-643.

叶俊,石学法,杨耀民,等.西南印度洋超慢速扩张脊49.6°E 热液区硫化物矿物学特征及其意义[J].矿物学报,2011,31(1): 17-29.

Sun S S,McDonough W F. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes[J]. Geological Society of London,1989,42: 313-345.

Campbell A C,Palmer M R,Klinkhammer G P,et al. Chemistry of hot springs on the Mid-Atlantic Ridge[J]. Nature,1988,335: 514-519.

Marques A F A,Barriga F,Chavagnac V,et al. Mineralogy,geochemistry,and Nd isotope composition of the Rainbow hydrothermal field,Mid-Atlantic Ridge[J]. Mineralium Deposita,2006,41(1): 52-67.

Mills R A,Elderfield H. Rare earth element geochemistry of hydrothermal deposits from the active TAG Mound,26°N Mid-Atlantic Ridge[J]. Geochimica et Cosmochimica Acta,1995,59(17): 3511-3524.

Barrat J A,Boulegue J,Tiercelinet J J,et al. Strontium isotopes and rare-earth element geochemistry of hydrothermal carbonate deposits from Lake Tanganyika,East Africa[J]. Geochimica et Cosmochimica Acta,2000,64(2): 287-298.

Puchelt H,Emmermann R. REE characteristics of ocean floor basalts from the MAR 37°N (Leg 37 DSDP)[J]. Contributions Mineralogy Petrology,1977,62: 43-52.

Tiezzi L J,Scott R B.Crystal fractionation in a cumulate gabbro,Mid-Atlantic Ridge,26°N[J].Journal of Geophysical Research,1980,85: 5438-5454.

Paulicka H,Bachb W,Godardc M,et al. Geochemistry of abyssal peridotites (Mid-Atlantic Ridge,15°20'N,ODP Leg 209): implications for fluid/rock interaction in slow spreading environments[J]. Chemical Geology,2006,234(3/4): 179-210.

Zeng Zhigang,Wang Qiaoyun,Wang Xiaomei,et al. Geochemistry of abyssal peridotites from the super slow-spreading Southwest Indian Ridge near 65°E:implications for magma source and seawater alteration[J].Journal of Earth System Science,2012,121(5): 1317-1336.

Niu Y. Bulk-rock major and trace element compositions of abyssal peridotites: implications for mantle melting,melt extraction and post-melting processes beneath mid-ocean ridges[J]. Journal of Petrology,2004,45(12): 2423-2458.

Campbell I H,Lesher C M,Coad P,et al. Rare-earth element mobility in alteration pipes below massive Cu-Zn sulfide deposits[J].Chemical Geology,1984,45: 181-202.

Lesher C M,Gibson H L,Campbell I H. Composition-volume changes during hydrothermal alteration of andesite at Buttercup Hill,Noranda District,Quebec[J]. Geochimica et Cosmochimica Acta,1986,50: 2693-2705.

Whitford D J,Korsch M J,Porritt P M,et al. Rare-earth element mobility around the volcanogenic polymetallic massive sulfide deposit at Que River,Tasmania,Australia[J]. Chemical Geology,1988,68: 105-119.

Graf J L. Rare earth elements as hydrothermal tracers during the formation of massive sulfide deposits in volcanic rocks[J].Economic Geology,1977,72(4): 527-548.

Bence A E,Taylor B E. Rare earth element systematics of West Shasta metavolcanic rocks:petrogenesis and hydrothermal alteration[J]. Economic Geology,1985,80: 2164-2176.

Michard A.Rare earth element systematics in hydrothermal fluids[J].Geochimica et Cosmochimica Acta,1989,53: 745-750.

Barrett T J,Jarvis I,Jarvis K E. Rare-earth element geochemistry of massive sulfides-sulfates and gossans on the southern explorer ridge[J].Geology,1990,18(7): 583-586.

Gammons C H,Wood S A,Williams-Jones A E. The aqueous geochemistry of the rare earth elements and Y: VI.Stability of neodynium chloride complexes from 25 to 300℃[J]. Geochimica et Cosmochimica Acta,1996,60(23): 4615-4630.

Shmulovich K,Heinrich W,Moller P,et al. Experimental determination of REE fractionation between liquid and vapour in the systems NaCl-H₂O and CaCl₂-H₂O up to 450℃[J]. Contributions to Mineralogy and Petrology,2002,144(3): 257-273.

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