Multiple Parameters Enable Deconvolution of Water-Rock Reaction Paths in Low-Temperature Vent Fluids of the Kamaʻehuakanaloa (Lō’ihi) Seamount
Multiple Parameters Enable Deconvolution of Water-Rock Reaction Paths in Low-Temperature Vent Fluids of the Kamaʻehuakanaloa (Lō’ihi) Seamount
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多个参数可对 Kamaehuakanaloa (Lō’ihi) 海山低温喷口流体中的水-岩石反应路径进行反褶积
DOI：
10.1016/j.gca.2023.03.013
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发表时间：
2023
影响因子：
5
通讯作者：
C. German
中科院分区：
文献类型：
--
作者：
V. Milesi;E. Shock;J. Seewald;E. Trembath;S. Sylva;J. Huber;Darlene S. S. Lim;C. German
洋中脊喷发流体对全球海洋生物地球化学循环的贡献已得到充分认识。人们对岩浆活跃的板块内火山的作用知之甚少。在这项研究中，研究人员从夏威夷群岛Kama wai ehuakanaloa（以前称为lhi wai ihi）海山的20至50°C喷口流体中获得了新的流体成分数据，并用于模拟各种反应条件，这些反应条件能够产生观察到的富铁、富硅和富二氧化碳的喷口流体。我们的概念模型包括第一步，随着温度的升高，海水与玄武岩和气体的比例增加，第二步，产生的热液流体与未改变的海水混合，同时继续与玄武岩反应，直到流体混合物达到20°C。选择了一系列不同的反应路径：步骤1的最高温度（50 ~ 400℃）和玄武岩与气体反应的比例；步骤2中低温玄武岩蚀变的程度F，对应于步骤1中产生的热流体上升到海底时继续与更多玄武岩反应的程度。我们的模型表明，在流体上涌过程中，20-50℃的喷口流体很大程度上取决于低温玄武岩蚀变的程度。事实上，Kama ha . ehuakanaloa喷口流体的组成不能与高温端元喷口流体与海水单独的地下力学混合的一般模型相一致。相反，它们需要≥350°C的热液端元与海水之间的地下平衡混合，以及当流体混合物上升到海底时必须发生的进一步玄武岩蚀变。虽然在步骤1中只涉及到约4%的玄武岩反应量，但在步骤2中的这种低温玄武岩蚀变导致了在Kama ha ehuakanaloa喷口流体中观察到的铁的特征富集和伴随的H2S的耗尽。我们假设，在流体上涌通过海底的延伸路径中，低温玄武岩蚀变可能是由Kama ha . ehuakanaloa海山的高度和陡峭的地形直接导致的。如果正确的话，这表明了一个更普遍的情况——岩浆活动的板内火山的输入，在迄今为止的海底喷口调查历史中相对被忽视，可能与全球洋中脊通量有很大不同，并且比以前认识到的对全球海洋铁循环的贡献更大。
The contribution of venting fluids at mid-ocean ridges to global ocean biogeochemical cycles is well recognized. Less is known about the role of magmatically-active intra-plate volcanoes. In this study, new compositional fluid data were acquired from 20 to 50 °C vent fluids at Kamaʻehuakanaloa (previously known as Lōʻihi) seamount (Hawai’ian archipelago) and used to model the wide diversity of reaction conditions capable of producing the Fe-, Si- and CO2-rich vent fluids observed. Our conceptual model includes a first step where seawater reacts with increasing proportions of basalt and gas as the temperature increases, and a second step where the resulting hydrothermal fluid mixes with unaltered seawater while continuing to react with basalt until the fluid mixture reaches 20 °C. A series of reaction paths were chosen to vary: the maximum temperature during Step 1 (50 to 400 °C) and the proportions of basalt and gas reacting; the degree,F, of low-temperature basalt alteration during Step 2, which corresponds to the extent to which the hot fluid generated during Step 1 continues to react with more basalt as it ascends to the seafloor. Our model shows that the 20–50 °C vent fluids are greatly dependent on the degree of low-temperature basalt alteration during fluid upwelling. Indeed, the compositions of Kamaʻehuakanaloa vent fluids cannot be reconciled with a general model of subsurface mechanical mixing of high-temperature end-member vent fluid and seawater alone. Instead, they require both subsurface equilibrium mixing between a ≥350 °C hydrothermal fluid end-member and seawater and further basalt alteration that must occur as the fluid mixture rises to the seafloor. Although it involves only ∼4% of the amount of basalt having reacted during Step 1, this low-temperature basalt alteration during Step 2 leads to the characteristic enrichments in Fe observed in the Kamaʻehuakanaloa vent fluids and a concomitant depletion in H2S. We hypothesize that low-temperature basalt alteration during an extended path of fluid upwelling through the subseafloor might arise as a direct consequence of the height and steep-sloped topography of Kamaʻehuakanaloa seamount. If correct, this suggests a more general case - that input from magmatically-active intraplate volcanoes, which have been relatively overlooked throughout the history of submarine vent investigations to date, could differ significantly from global mid-ocean ridge fluxes and contribute more substantially than previously recognized to the global ocean Fe cycle.
DOI：
10.1098/rsta.2018.0431
发表时间：
2020-02-21
影响因子：
5
作者：
Grozeva, Niya G.;Klein, Frieder;Sylva, Sean P.
通讯作者：
Sylva, Sean P.
影响因子：
5.3
作者：
Danielle P. Santiago Ramos;L. A. Coogan;Jack Geary Murphy;J. Higgins
通讯作者：
Danielle P. Santiago Ramos;L. A. Coogan;Jack Geary Murphy;J. Higgins
DOI：
10.1073/pnas.1907871116
发表时间：
2019-09-03
影响因子：
11.1
作者：
Klein, Frieder;Grozeva, Niya G.;Seewald, Jeffrey S.
通讯作者：
Seewald, Jeffrey S.