Active hydrothermal discharge on the submarine Aeolian Arc
Active hydrothermal discharge on the submarine Aeolian Arc
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海底风弧的活跃热液排放
DOI：
10.1029/2010jb007738
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发表时间：
2011
影响因子：
--
通讯作者：
R. Greene
中科院分区：
文献类型：
--
作者：
J. Lupton;C. D. Ronde;M. Sprovieri;E. Baker;P. Bruno;F. Italiano;S. Walker;K. Faure;M. Leybourne;K. Britten;R. Greene
[1] 2007 年 11 月，我们在 R/V Urania 号上对第勒尼安海南部的风神弧海底火山进行了水柱和海底测绘研究。在 26 个电导率-温度深度铸件和丝束中，我们测量了温度、电导率、压力和光散射，并收集了氦同位素、甲烷和 pH 值的离散样本。 3He/4He 同位素比是热液输入的明确指标，在所调查的 10 座海底火山中，有 6 座显示出明显超出背景值。马西里海山异常最高，610 m 深度处 3He/4He 比值达到 23%，而背景值约为 5%。 Palinuro、Enarete、Eolo、Sisifo 和 Secca del Capo 上空出现了较小但明显的 δ3He 异常。尽管已知热液排放发生在一些风沙陆上火山的近海，并且在整个弧区都对热液沉积物进行了采样，但我们的结果首次证实了马西利、埃纳雷特、埃奥洛、西西福和塞卡德尔卡波的活跃排放。在 Lametini、Filicudi North、Alicudi North 和 Alcione 收集的样本的 δ3He 接近区域背景值，表明这些海山不存在热液活动或非常弱。火山之间的水力铸造显示，整个第勒尼安海 2000 米深度处的 δ3He 最大值一致在 11% 到 13% 之间。伊奥利亚弧和马西里后弧的火山深度均小于 1000 米，无法直接促成这一最大值。这种深层 3He 过量可能是氚衰变的残余物，也可能是由未知的深层热液源产生的。
[1] In November 2007 we conducted a water column and seafloor mapping study of the submarine volcanoes of the Aeolian Arc in the southern Tyrrhenian Sea aboard the R/V Urania. On 26 conductivity-temperature-depth casts and tows we measured temperature, conductivity, pressure, and light scattering and also collected discrete samples for helium isotopes, methane, and pH. The 3He/4He isotope ratio, an unambiguous indicator of hydrothermal input, showed a clear excess above background at 6 of the 10 submarine volcanoes surveyed. Marsili seamount had the highest anomaly, where the 3He/4He ratio reached a δ3He value of 23% at 610 m depth compared with background values of ∼5%. Smaller but distinct δ3He anomalies occurred over Palinuro, Enarete, Eolo, Sisifo, and Secca del Capo. Although hydrothermal emissions are known to occur offshore of some Aeolian subaerial volcanoes, and hydrothermal deposits have been sampled throughout the arc, our results are the first to confirm active discharge on Marsili, Enarete, Eolo, Sisifo, and Secca del Capo. Samples collected over Lametini, Filicudi North, Alicudi North, and Alcione had δ3He near the regional background values, suggesting either absence of, or very weak, hydrothermal activity on these seamounts. Hydrocasts between the volcanoes revealed a consistent δ3He maximum between 11% and 13% at 2000 m depth throughout the SE Tyrrhenian Sea. The volcanoes of the Aeolian arc and the Marsili back arc, all <1000 m deep, cannot contribute directly to this maximum. This deep 3He excess may be a remnant of tritium decay or may have been produced by an unknown deep hydrothermal source.