EPR 9°~10°N L喷口黑烟囱体形成环境重建:来自矿物学及铅-210年龄的限制
Restructuring the formation conditions of black smoker chimney from L vent EPR 9°~10°N:constraints from mineralogy and lead-210 age
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摘要: 为了重建EPR 9°~10°N L喷口的形成环境,采用矿物学、地球化学及年代学的方法,对黑烟囱体的矿物组成、矿物结构、元素剖面分布以及黑烟囱体内外层铅-210测年进行了研究。矿物学观察表明,该喷口烟囱体内壁主要由方黄铜矿组成,而外壁则主要由硬石膏组成。铅-210测年结果表明,烟囱体形成于EPR 9°~10°N区域内1991年的火山喷发事件之后,并有较低的生长速率,约为0.3cm/a。结合该喷口及其附近A喷口已发表资料认为,该烟囱体开始生长是由于蒸气相流体引起的,其后期受到卤水相流体的影响,而且流体温度应不小于330℃。Abstract: For restructuring the formation conditions of the black smoker chimney from L vent EPR 9°~10°N,mineralogy,the distribution of elements,and the ages of this chimney were studied with mineralogical,geochemical and radioactive chronological methods.Mineral observations show that the inner wall of this chimney is composed of cubanite,and the outer wall of the chimney is mainly composed of anhydrite.The results of lead-210 age show that the chimney forms after the 1991 EPR volcanic eruption events and has a slower growth rate,about 0.3 cm/a.Combining these results with the published data about A vent,nearby L vent,it is suggested that this chimney begins growth with a vapor phase fluid,and later is influenced by a brine phase fluid with temperature not less than 330℃.
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Key words:
- EPR 9° /
- ~10° /
- N /
- L vent:black smoker chimney /
- hydrothermal system /
- cubanite /
- lead-210 age /
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HANNINGTON M D,CORNEL E J,PETERSEN S.Sea floor tectonics and submarine hydrothermal systems[G]//HEDENQuIST J W,THOMPSON J F H,GOLDFARB R J,et al.Economic Geology,One hundredth anniversary volume.2005:111-141. ANDRIEU A S.HONNOREZ J J,LANCEI.OT J.Lead isotope compositions of the TAG mineralization,Mid-Atlantic Ridge,26°08' N[J].Proceedings of the Ocean Drilling Program:Scientific Results,1998,158:101-109. HERZIG P M,PETERSEN S,HANNINGTON M D Geochemistry and sulfur-isotopic composition of the TAG hydrothermal mound,Mid-Atlantic Ridge,26°N[J].Proceedings of the Ocean Drilling Program:Scientific Results,1998,158:47-70. HAYMON R M,FORNARI D J,EDWARDS M H,et al.Hydrothermal vent distribution along the East Pacific Rise crest(9°09'-54'N)and its relationship to magmatic and tectonic processes on fast-spreading mid-ocean ridges[J].Earth Planet Sci Lett,1991,104:513-534. HAYMON R M,FORNARI D J,VON DAMM K L,et al.Volcanic eruption of the mid-ocean ridge along the East Pacific Rise crest at 9°5'-52'N:direct submersible observations of seafloor phenomena associated with an eruption event in April,1991[J].Earth Planet Sei Lett,1993.119:85-101. VON DAMM K L.Chemistry of hydrothermal vent fluids from 9°-10°N,East Pacific Rise:"Time zero,"the immediate posteruptive period[J].J Geophys Res,2000,105:11203-11222. VON DAMM K L.Evolution of the hydrothermal system at East Pacific Rise 9°54'N:geochemical evidence for changes in the upper oce-anic crust[G]//GERMAN C R,LIN J,PARSON L M.Mid-Ocean Ridges:Hydrothermal Interactions between the Lithosphere and Oceans.2004:285-304. VON DAMM K,OOSTING S E,KOZLOWSK L,et al.Evolution of East Pacific Rise hydrothermal vent fluids following a volcanic e-ruption[J].Nature.1995,375:47-50. RUBIN K H,MACDOUGALL J D,PERFIT M R.(210)~Po/(210)~Pb dating of recent volcanic eruptions on the sea floor[J].Nature,1994,368:841-844. PENG X T.ZHOU H Y.Growth history of hydrothermal chimneys at EPR 9°-10°N:a structural and mineralogical study[J].Science in China:Ser D,Earth Science,2005,48:1891-1899. 苏琼,李允兴.GB/T11713-89用半导体γ谱仪分析低比活度γ放射性样品的标准方法[S].北京:中国标准出版社. FORNARI D J,SHANK Tt VON DAMM K L,et al.Time-series temperature measurements at high-temperature hydrothermal vents,East Pacific Rise 9°49'-51'N:evidence for monitoring a crustal cracking event[J].Earth Planet Sci Lett,1998.180:419-431. AUCLAIR G,FOUQUET Y,BOHN M.Distribution of selenium in high-temperature hydrothermal sulfide deposits at 13°North,East Pacific Rise[J].Canadian Mineralogist,1987,25:577-588. HANNINGTON M D,HERZIG P,SCOTT S,et al.mineralogy and geochemistry of gold-bearing sulfide deposits on the mid-ocean rid-ges[J].Marine Geology,1991,101:217-248. FOUQUET Y,WAFIK A,CAMBON P,et al.Tectonic setting and mineralogical and geochemical zonation in the Snake Pit sulfide de-posit(Mid-Atlantic Ridge at 23°N)[J].Economic Geology,1993,88:2018-2036. TIVEY M K,STAKES D S,COOK T L,et al.A model for growth of steep-sided vent structures on the Endeavour Segment of the Juan de Fuca Ridge:results of a petrologic and geochemical study[J].J Geophys Rest 1999,104:22859-22883. LALOU C,BRICHET E,HEKINIAN R.Age dating of sulfide deposits from axial and off-axial structures on the East Pacific Rise near 12°50'N[J].Earth Planet Sci Lett,1985,75:59-71. KADKO D,KOSKI R,TATSUMOTO M,et al.An estimate of hydrothermal fluid residence times and vent chimney growth rates based on 210pb/Pb ratios and mineralogical studies of sulfides dredged from the Juan de Fuca Ridge[J].Earth Planet Sci Lett,1985,76:35-44. REYES A O,MOORE W S,STAKES D S.228Th/228Ra ages of a barite-rich chimney from the Endeavour Segment of the Juan de Fuca Ridge[J].Earth Planet Sci Lett,1995,131:99-113. BISCHOFF J L,ROSENBAUER R J.Liquid-vapor relations in the critical region of the system NaCI-H2O from 380 to 415℃:a refined deter-ruination of the critical point and two-phase boundary of seawater[J].Geochimica et Cosmochimica Acta,1988,52:2121-2126. BISCHOFF J L,PITZER K S.Liquid-vapor relations for the system NaCI-H2O:Summary of the P-T-X surface from 300 to 500℃[J].American Journal of Science,1989,289:217-248. VON DAMM K L,BUTTERMORE L G,POSTING S E,et al,Direct observation of the evolution of a seafloor ‘black smoker'from vapor to brine[J].Earth Planet Sci Lett,1997,149:101-111. RAVIZZA G,BLUSZTAJIN J,VON DAMM K L,et al.Sr isotope variations in vents fluids from 9°46'-9°54' East Pacific Rise:evi-dence of a non-zero-Mg fluid component[J].Geochimica et Cosmochimica Acta,2001,65:729-739. SCHMIDT K,KOSCHINSKY A,GARBE-SCHBERG D,et al.Geochemistry of hydrothermal fluids from the ultramafic-hosted Lo-gatchev hydrothermal field,15°on the Mid-Atlantic Ridge:temporal and spatial investigation[J].Che Geo,2007,242:1-21. BUTTERFIELD D A,MASSOTH G J.Geochemistry of north Cleft segment vent fluids:temporal changes in chlorinity and their possi-ble relation to recent volcanism[J].J Geophys Res,1994,99:4951-4968. BUTTERFIELD D A,MCDUFF R E,MOTTL M J,et al.Gradients in the composition of hydrothermal fluids from the Endeavour segment vent field:phase separation and brine loss[J].J Geophys Res,1994,99:9561-9583. BUTTERFIELD D A,MASSOTH G J,MCDUFF R E,et al.Geochemistry of hydrothermal fluids from axial seamount hydrothermal emissions study vent field,Juan de Fuca Ridge:subseafloor boiling and subsequent fluids-rock interaction[J].J Geophys Res,1990,95:12895-12921. HAYMON R M.Growth history of hydrothermal black smoker chimney[J].Nature,1983,301:695——698. TIVYE M K,DELANEY J R.Growth of large sulfide structures on the Endeavour Segment of the Juan de Fuca Ridge[J].Earth Planet Sci Lett,1986,77:303-317. BAKER E T,MCDUFF R E,MASSOTH G J.Hydrothermal venting from the summit of a ridge axis seamount:Axial Volcano,Juan de Fuca Ridge[J].J Geophys Res,1990,95:12843-12854. LUSK J,CALDER B O E.The composition of sphalerite and associated sulfides in reactions of the Cu-Fe-Zn-S,Fe-Zn-S and Cu-Fe-Ssystems at 1 bar and temperatures between 250 and 535 ℃[J].Che Geo,2004,203..319-345. LUSK J,MAXWELL B D.Phase relations and the electrochemical determination of sulfur fugacity for selected reactions in the Cu-Fe-S and Fe-S systems at 1 bar and temperatures between 185 and 460℃[J].Che Geo,2002,192:227-248.
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