Fluid venting

Deciding whether the fluid vented will be single or two-phase... 

Hunt, 1996) and because fluids vented on the seafloor show evidence of long-distance transport (e.g., papers in Parnell, 1998). Major transfers of CO2, Ca, Si, and K have also been proposed, but they remain controversial, largely because the apparent permeabihty of thick shale-dominated sequences appears very inadequate to permit a large amount of advective transport (Bjprlykke, 1989, 1993 Bjprlykke and Lynch, 1997). 

Cragg, B.A., Summit, M. and Parkes, RJ. (2000) Bacterial profiles in a sulfide mound (Site 1035) and an area of active fluid venting (Site 1036) in hot hydrothermal sediments from Middle Valley (Northeast Pacific), in Proceedings of the Ocean Drilling Program, Initial Reports, vol. 169 (eds R.A. Zierenberg, Y. Fouquet, DJ. Miller and W.R. Normark), pp. 1—18 [online]. 

Suess, E., Bohrmann, G., von Huene, R., Linke, P., Wallmann, K., Lammers, S., Sahling, H., Winckler, G. and Lutz, R.A. (1998) Fluid venting in the eastern Aleutian subduction zone. Journal of Geophysical Research, B103, 2597-2614. 

However, this is only one approach to estimate permeabilities from porosities and mean grain sizes. Other empirical relations exist, particularly for regions with hydrocarbon exploration (e.g. Gulf of Mexico, Bryant et al. 1975) or fluid venting (e.g. Middle Valley, Fisher et al. 1994) which compute depth-dependent permeabilities from porosity logs or take the grain size distribution and clay content into account. 

Mazurenko, L.L., and Soloviev, V.A., 2003. Worldwide distribution of deep-water fluid venting and potential occurrences of gas hydrate accumulations. Geo-Marine Letters, 23 162-176. 

The pressure at 1000 m depth is 100 bars (10 m = 1 bar). The maximum temperature of venting is determined by the pressure on the two-phase curve for seawater (Fig. 13.8). At 1000 m or 100 bars, a hydrothermal fluid venting at the seafloor cannot be hotter than about 310°C. At 500 m depth or 50 bars, the maximum temperature will be about 270°C. 

Although volatile flux estimates from back-arc regions vary greatly, the situation is even more poorly constrained for fore-arc regions. We are unaware of any flux estimates for either major volatiles or noble gases. This is in spite of abundant circumstantial evidence for fluid venting in fore-arc regions e.g., serpentinite diapirism in the Marianas (Fryer et al. 1985) and mud volcanism at various accretionary prisms worldwide (Brown... 

Vent fluids Vent sulphides Vent sedimcnE Basalt Anhydrite. Seawater... 

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