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Volume 56 Supplement 2

Special Issue: Special section for IUGG workshop: Lithospheric Structure of a Supercontinent:Gondwana

Numerical simulations of mid-ocean ridge hydrothermal circulation including the phase separation of seawater

An Erratum to this article was published on 24 June 2014

Abstract

Phase separation of seawater is an important process controlling the dynamics and chemistry of hydrothermal circulation. We numerically investigate hydrothermal circulation in porous media, including phase separation of seawater. Seawater enters the crust at the seafloor, is heated at depth, and returns to the seafloor as hydrothermal fluids. The seafloor and the bottom of the calculation region are set at depths of 2500 m and 4000 m from the sea surface, respectively. The temperature at the base of the calculation region is set at 600°C. Under these pressure and temperature ranges, supercritical phase separation is inevitable. Here we focus on steady-state conditions, as a first step to investigate the complex process of convection with phase separation. Under these conditions, we demonstrate that phase separation leads to a two-layer structure. Seawater circulates vigorously in the upper layer, and this overlies a stagnant lower layer formed by sinking of dense brine. We find that the key quantity which governs this structure is the ratio of the relative velocity between the two phases to the mean flow velocity in the transition zone between the two layers. As the relative velocity increases, the brine layer becomes thick, and the transition zone becomes thin. Under steady state conditions, the mean salinity at the seafloor should be the same as that of seawater because the total mass of salt should be conserved. Fluids which vent near the ridge axis are more saline than seawater, whereas fluids which vent more than about 100 m away from the axis are less saline than seawater.

References

  • Anderko, K. and K. S. Pitzer, Equation-of-state representation of phase equilibria and volumetric properties of the system NaCl-H2O above 573 K, Geochim. Cosmochim. Acta, 57, 1657–1680, 1993.

    Article  Google Scholar 

  • Bai, W. M., W. Y. Xu, and R. P. Lowell, The dynamics of submarine geother-mal heat pipes, Geophys. Res. Lett., 30, doi:10.1029/2002GL016176, 2003.

  • Batchelor, G. K., An Introduction to Fluid Dynamics, 635 pp., Cambridge University Press, Cambridge, 1967.

    Google Scholar 

  • Bear, J., Dynamics of Fluids in Porous Media, 764 pp., Dover, New York, 1988.

    Google Scholar 

  • Becker, K., Measurements of the permeability of the sheeted dikes in Hole 504B, ODP LEG 111, Proc. Ocean Dril. Prog., Sci. Results, 111, 317–325, 1989.

    Google Scholar 

  • Berndt, M. E. and W. E. Seyfried, Jr., Boron, bromine, and other trace elements as clues to the fate of chlorine in mid-ocean ridge vent fluids, Geochim. Cosmochim. Acta, 54, 2235–2245, 1990.

    Article  Google Scholar 

  • Bischoff, J. L. and R. J. Rosenbauer, Salinity variations in submarine hydrothermal systems by layered double-diffusive convection, J. Geol., 97, 613–623, 1989.

    Article  Google Scholar 

  • Blankenbach, B., F. Busse, U. Christensen, L. Cserepes, D. Gunkel, U. Hansen, H. Harder, G. Jarvis, M. Koch, G. Marquart, D. Moore, P. Olson, H. Schmeling, and T. Schnaubelt, A Benchmark comparison for mantle convection codes, Geophys. J. Int., 98, 23–38, 1989.

    Article  Google Scholar 

  • Butterfield, D. A., G. J. Massoth, R. E. McDuff, J. E. Lupton, and M. D. Lilley, Geochemistry of hydrothermal fluids from Axial Seamount Hydrothermal Emissions Study vent field, Juan de Fuca ridge: subseafloor boiling and subsequent fluid-rock interaction, J. Geophys. Res., 95, 12895–12921, 1990.

    Article  Google Scholar 

  • Cherkaoui, A. S. M. and W. S. D. Wilcock, Characteristics of high Rayleigh number two-dimensional convection in an open-top porous layer heated from below, J. Fluid Mech., 394, 241–260, 1999.

    Article  Google Scholar 

  • Christensen, U., Convection with pressure- and temperature-dependent non-Newtonian rheology, Geophys. J. R. astr. Soc, 77, 343–384, 1984.

    Article  Google Scholar 

  • Elder, J. W., Steady free convection in a porous medium heated from below, J. Fluid Mech., 27, 29–48, 1967.

    Article  Google Scholar 

  • Fehn, U., K. E. Green, R. P. Von Herzen, and L. M. Cathles, Numerical models for the hydrothermal field at the Galapagos spreading center, J. Geophys. Res., 88, 1033–1048, 1983.

    Article  Google Scholar 

  • Fisher, A. T., Permeability within basaltic oceanic crust, Rev. Geophys., 36, 143–182, 1998.

    Article  Google Scholar 

  • Fontaine, F. Jh., M. Rabinowicz, and J. Boulègue, Permeability changes due to mineral diagenesis in fractured crust: Implications for hydrothermal circulation at mid-ocean ridges, Earth Planet. Sci. Lett., 184, 407–425, 2001.

    Article  Google Scholar 

  • Fornari, D. J. and R. W. Embley, Tectonic and volcanic controls on hydrothermal processes at the mid-ocean ridge: An overview based on near-bottom and submersible studies, in Seafloor Hydrothermal Systems: Physical, Chemical, Biological, and Geological Interactions, Geophys. Monogr., vol. 91, edited by S. E. Humphris et al., pp. 1–46, AGU, Washington, D.C., 1995.

    Google Scholar 

  • Fournier, R. O., Conceptual models of brine evolution in magmatic-hydrothermal systems, U. S. Geol. Surv. Prof. Pap., 1350, 1487–1506, 1987.

    Google Scholar 

  • Haar, J. L., J. S. Gallagher, and G. S. Kell, NBS/NRC Steam Tables: Thermodynamic and Transport Properties and Computer Programs for Vapor and Liquid States of Water in SI units, 320 pp., Hemisphere, New York, 1984.

    Google Scholar 

  • Ishii, M., Thermo-Fluid Dynamic Theory of Two-Phase Flow, 248 pp., Eyrolles, Paris, 1975.

    Google Scholar 

  • Jupp, T. and A. Schultz, A thermodynamic explanation for black smoker temperatures, Nature, 403, 880–883, 2000.

    Article  Google Scholar 

  • Kelley, D. S., P. T. Robinson, and J. G. Malpas, Processes of brine generation and circulation in the oceanic crust: Fluid inclusion evidence from the Troodos Ophiolite, Cyprus, J. Geophys. Res., 97, 9307–9322, 1992.

    Article  Google Scholar 

  • Kelley, D. S., J. A. Baross, and J. R. Delaney, Volcanoes, fluids, and life at mid-ocean ridge spreading centers, Annu. Rev. Earth Planet. Sci., 30, 385–491, 2002.

    Article  Google Scholar 

  • Koshizuka, S., Computational Fluid Dynamics, 223 pp., Baifukan, Tokyo, 1997 (in Japanese).

    Google Scholar 

  • Lasaga, A. C, Kinetics Theory in the Earth Sciences, 811 pp, Princeton University Press, Princeton, New Jersey, 1998.

    Book  Google Scholar 

  • Lowell, R. P., Modeling continental and submarine hydrothermal systems, Rev. Geophys., 29, 457–476, 1991.

    Article  Google Scholar 

  • Lowell, R. P. and L. N. Germanovich, Evolution of a brine-saturated layer at the base of a ridge-crest hydrothermal system, J. Geophys. Res., 102, 10245–10255, 1997.

    Article  Google Scholar 

  • Lowell, R. P. and W. Xu, Sub-critical two-phase seawater convection near a dike, Earth Planet. Sci. Lett., 174, 385–396, 2000.

    Article  Google Scholar 

  • Lowell, R. P., P. A. Rona, and R. P. Von Herzen, Seafloor hydrothermal systems, J. Geophys. Res., 100, 327–352, 1995.

    Article  Google Scholar 

  • Martin, J. T. and R. P. Lowell, Precipitation of quartz during high-temperature, fracture-controlled hydrothermal upflow at ocean ridges: Equilibrium versus linear kinetics, J. Geophys. Res., 105, 869–882, 2000.

    Article  Google Scholar 

  • Mével, C. and M. Cannat, Lithospheric stretching and hydrothermal processes in oceanic gabbros from slow-spreading ridges, in Ophiolite Genesis and Evolution of the Oceanic Lithosphere, edited by Tj. Peters et al., pp. 293–312, Kluwer Academic, Dordrecht, 1991.

    Chapter  Google Scholar 

  • Nehlig, P., Fracture and permeability analysis in magma-hydrothermal transition zones in the Samail ophiolite (Oman), J. Geophys. Res., 99, 589–601, 1994.

    Article  Google Scholar 

  • Nehlig, P. and T. Juteau, Flow porosities, permeabilities, and preliminary data on fluid inclusions and fossil thermal-gradients in the crustal sequence of the Sumail ophiolite (Oman), Tectonophys., 151, 199–221, 1988.

    Article  Google Scholar 

  • Nield, D. A. and A. Bejan, Convection in Porous Media, second edition, 546 pp., Springer-Verlag, New York, 1999.

    Book  Google Scholar 

  • Palliser, C. and R. McKibbin, A model for deep geothermal brines, I: T-p- Xstate-space description, Transport in Porous Media, 33, 65–80, 1998a.

    Article  Google Scholar 

  • Palliser, C. and R. McKibbin, A model for deep geothermal brines, III: Thermodynamic properties—Enthalpy and viscosity, Transport in Porous Media, 33, 155–171, 1998b.

    Article  Google Scholar 

  • Pitzer, K. S., J. C. Peiper, and R. H. Busey, Thermodynamic properties of aqueous sodium chloride solutions, J. Phys. Chem. Ref. Data, 13, 1–102, 1984.

    Article  Google Scholar 

  • Raithby, G. D., Skew upstream differencing schemes for problems involving fluid flow, Comp. Methods Appl. Mech. Eng., 9, 153–164, 1976.

    Article  Google Scholar 

  • Schoofs, S. and U. Hansen, Depletion of a brine layer at the base of ridge-crest hydrothermal systems, Earth Planet. Sci. Lett., 180, 341–353, 2000.

    Article  Google Scholar 

  • Schoofs, S. and F. J. Spera, Transition to chaos and flow dynamics of thermochemical porous medium convection, Transport in Porous Media, 50, 179–195, 2003.

    Article  Google Scholar 

  • Schoofs, S., F. J. Spera, and U. Hansen, Chaotic thermohaline convection in low-porosity hydrothermal systems, Earth Planet. Sci. Lett., 174, 213–229, 1999.

    Article  Google Scholar 

  • Schoofs, S., R. A. Trompert, and U. Hansen, The formation and evolution of layered structures in porous media: Esffects of porosity and mechanical dispersion, Phys. Earth Planet. Int., 118, 205–225, 2000.

    Article  Google Scholar 

  • Sinton, J. M. and R. S. Detrick, Mid-ocean ridge magma chambers, J. Geophys. Res., 97, 197–216, 1992.

    Article  Google Scholar 

  • Travis, B. J., D. R. Janecky, and N. D. Rosenberg, Three-dimensional simulation of hydrothermal circulation at mid-ocean ridges, Geophys. Res. Lett., 18, 1441–1444, 1991.

    Article  Google Scholar 

  • Von Damm, K. L., Controls on the chemistry and temporal variability of seafloor hydrothermal fluids, in Seafloor Hydrothermal Systems: Physical, Chemical, Biological, and Geological Interactions, Geophys. Monogr., vol. 91, edited by S. E. Humphris et al., pp. 222–247, AGU, Washington, D.C., 1995.

    Google Scholar 

  • Von Damm, K. L., M. D. Lilley, W. C. Shanks, III, M. Brockington, A. M. Brey, K. M. O’Grady, E. Olson, A. Graham, G. Proskurowski, and the SouEPR Science Party, Extraordinary phase separation and segregation in vent fluids from the southern East Pacific Rise, Earth Planet. Sci. Lett., 206, 365–378, 2003.

    Article  Google Scholar 

  • Wilcock, W. S. D., Cellular convection models of mid-ocean ridge hydrothermal circulation and the temperatures of black smoker fluids, J. Geophys. Res., 103, 2585–2596, 1998.

    Article  Google Scholar 

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Correspondence to Yoshifumi Kawada.

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An erratum to this article is available at http://dx.doi.org/10.1186/BF03352502.

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Kawada, Y., Yoshida, S. & Watanabe, Si. Numerical simulations of mid-ocean ridge hydrothermal circulation including the phase separation of seawater. Earth Planet Sp 56, 193–215 (2004). https://doi.org/10.1186/BF03353403

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  • DOI: https://doi.org/10.1186/BF03353403

Key words

  • Hydrothermal circulation
  • phase separation
  • porous media