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Brine Formation and Mobilization in Submarine Hydrothermal Systems: Insights from a Novel Multiphase Hydrothermal Flow Model in the System H2O–NaCl. Transp Porous Media 2020. [DOI: 10.1007/s11242-020-01499-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
AbstractNumerical models have become indispensable tools for investigating submarine hydrothermal systems and for relating seafloor observations to physicochemical processes at depth. Particularly useful are multiphase models that account for phase separation phenomena, so that model predictions can be compared to observed variations in vent fluid salinity. Yet, the numerics of multiphase flow remain a challenge. Here we present a novel hydrothermal flow model for the system H2O–NaCl able to resolve multiphase flow over the full range of pressure, temperature, and salinity variations that are relevant to submarine hydrothermal systems. The method is based on a 2-D finite volume scheme that uses a Newton–Raphson algorithm to couple the governing conservation equations and to treat the non-linearity of the fluid properties. The method uses pressure, specific fluid enthalpy, and bulk fluid salt content as primary variables, is not bounded to the Courant time step size, and allows for a direct control of how accurately mass and energy conservation is ensured. In a first application of this new model, we investigate brine formation and mobilization in hydrothermal systems driven by a transient basal temperature boundary condition—analogue to seawater circulation systems found at mid-ocean ridges. We find that basal heating results in the rapid formation of a stable brine layer that thermally insulates the driving heat source. While this brine layer is stable under steady-state conditions, it can be mobilized as a consequence of variations in heat input leading to brine entrainment and the venting of highly saline fluids.
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Galley CG, Jamieson JW, Lelièvre PG, Farquharson CG, Parianos JM. Magnetic imaging of subseafloor hydrothermal fluid circulation pathways. SCIENCE ADVANCES 2020; 6:eabc6844. [PMID: 33127681 PMCID: PMC7608804 DOI: 10.1126/sciadv.abc6844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 09/14/2020] [Indexed: 06/11/2023]
Abstract
Hydrothermal fluid circulation beneath the seafloor is an important process for chemical and heat transfer between the solid Earth and overlying oceans. Discharge of hydrothermal fluids at the seafloor supports unique biological communities and can produce potentially valuable mineral deposits. Our understanding of the scale and geometry of subseafloor hydrothermal circulation has been limited to numerical simulations and their manifestations on the seafloor. Here, we use magnetic inverse modeling to generate the first three-dimensional empirical model of a hydrothermal convection system. High-temperature fluid-rock reactions associated with fluid circulation destroy magnetic minerals in the Earth's crust, thus allowing magnetic models to trace the fluid's pathways through the seafloor. We present an application of this modeling at a hydrothermally active region of the East Manus Basin.
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Affiliation(s)
- Christopher G Galley
- Department of Earth Sciences, Memorial University of Newfoundland, St. John's, NL A1B 3X7, Canada.
| | - John W Jamieson
- Department of Earth Sciences, Memorial University of Newfoundland, St. John's, NL A1B 3X7, Canada
| | - Peter G Lelièvre
- Department of Mathematics and Computer Science, Mount Allison University, Sackville, NB E4L 1E2, Canada
| | - Colin G Farquharson
- Department of Earth Sciences, Memorial University of Newfoundland, St. John's, NL A1B 3X7, Canada
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Tao C, Seyfried WE, Lowell RP, Liu Y, Liang J, Guo Z, Ding K, Zhang H, Liu J, Qiu L, Egorov I, Liao S, Zhao M, Zhou J, Deng X, Li H, Wang H, Cai W, Zhang G, Zhou H, Lin J, Li W. Deep high-temperature hydrothermal circulation in a detachment faulting system on the ultra-slow spreading ridge. Nat Commun 2020; 11:1300. [PMID: 32157084 PMCID: PMC7064610 DOI: 10.1038/s41467-020-15062-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 02/14/2020] [Indexed: 11/23/2022] Open
Abstract
Coupled magmatic and tectonic activity plays an important role in high-temperature hydrothermal circulation at mid-ocean ridges. The circulation patterns for such systems have been elucidated by microearthquakes and geochemical data over a broad spectrum of spreading rates, but such data have not been generally available for ultra-slow spreading ridges. Here we report new geophysical and fluid geochemical data for high-temperature active hydrothermal venting at Dragon Horn area (49.7°E) on the Southwest Indian Ridge. Twin detachment faults penetrating to the depth of 13 ± 2 km below the seafloor were identified based on the microearthquakes. The geochemical composition of the hydrothermal fluids suggests a long reaction path involving both mafic and ultramafic lithologies. Combined with numerical simulations, our results demonstrate that these hydrothermal fluids could circulate ~ 6 km deeper than the Moho boundary and to much greater depths than those at Trans-Atlantic Geotraverse and Logachev-1 hydrothermal fields on the Mid-Atlantic Ridge. Magmatic and tectonic activity at mid-oceanic ridges can give detailed insights into high-temperature hydrothermal circulation of fluids. The authors here present geochemical and geophysical datasets that suggest a hydrothermal system penetrating the upper lithospheric mantle at an ultra-slow spreading mid-oceanic ridge.
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Affiliation(s)
- Chunhui Tao
- Key Laboratory of Submarine Geosciences, MNR, Second Institute of Oceanography, MNR, 310012, Hangzhou, China. .,School of Oceanography, Shanghai Jiao Tong University, 200240, Shanghai, China.
| | - W E Seyfried
- Department of Earth Sciences, University of Minnesota, Minneapolis, MN, 55455, USA.
| | - R P Lowell
- Department of Geosciences, Virginia Polytechnic and State University, Blacksburg, VA, 42061, USA
| | - Yunlong Liu
- Key Laboratory of Submarine Geosciences, MNR, Second Institute of Oceanography, MNR, 310012, Hangzhou, China.,College of Geoexploration Science and Technology, Jilin University, 130026, Changchun, China
| | - Jin Liang
- Key Laboratory of Submarine Geosciences, MNR, Second Institute of Oceanography, MNR, 310012, Hangzhou, China
| | - Zhikui Guo
- Key Laboratory of Submarine Geosciences, MNR, Second Institute of Oceanography, MNR, 310012, Hangzhou, China.,Institute of Geophysics and Geomatics, China University of Geosciences, 430074, Wuhan, Hubei, China
| | - Kang Ding
- Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, 572000, Sanya, China
| | - Huatian Zhang
- Department of Geophysics, School of Earth & Space Sciences, Peking University, 100871, Beijing, China
| | - Jia Liu
- Key Laboratory of Submarine Geosciences, MNR, Second Institute of Oceanography, MNR, 310012, Hangzhou, China
| | - Lei Qiu
- Key Laboratory of Submarine Geosciences, MNR, Second Institute of Oceanography, MNR, 310012, Hangzhou, China
| | - Igor Egorov
- The Federal State Budgetary Institution, Academician I.S. Gramberg All-Russia Scientific Research Institute for Geology and Mineral Resources of the Ocean, Saint-Petersburg, 190121, Russia
| | - Shili Liao
- Key Laboratory of Submarine Geosciences, MNR, Second Institute of Oceanography, MNR, 310012, Hangzhou, China
| | - Minghui Zhao
- Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 510301, Guangzhou, China
| | - Jianping Zhou
- Key Laboratory of Submarine Geosciences, MNR, Second Institute of Oceanography, MNR, 310012, Hangzhou, China
| | - Xianming Deng
- Key Laboratory of Submarine Geosciences, MNR, Second Institute of Oceanography, MNR, 310012, Hangzhou, China
| | - Huaiming Li
- Key Laboratory of Submarine Geosciences, MNR, Second Institute of Oceanography, MNR, 310012, Hangzhou, China
| | - Hanchuang Wang
- Key Laboratory of Submarine Geosciences, MNR, Second Institute of Oceanography, MNR, 310012, Hangzhou, China
| | - Wei Cai
- Key Laboratory of Submarine Geosciences, MNR, Second Institute of Oceanography, MNR, 310012, Hangzhou, China
| | - Guoyin Zhang
- Key Laboratory of Submarine Geosciences, MNR, Second Institute of Oceanography, MNR, 310012, Hangzhou, China
| | - Hongwei Zhou
- Key Laboratory of Submarine Geosciences, MNR, Second Institute of Oceanography, MNR, 310012, Hangzhou, China
| | - Jian Lin
- Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 510301, Guangzhou, China.,Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA
| | - Wei Li
- Key Laboratory of Submarine Geosciences, MNR, Second Institute of Oceanography, MNR, 310012, Hangzhou, China
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