In situ measurement of dissolved chloride in high temperature hydrothermal fluids

Permeability of the Lucky Strike deep-sea hydrothermal system: Constraints from the poroelastic response to ocean tidal loading

“…Our estimate is somewhat higher than the values obtained by methods that consider the entire crustal column, which is to be expected considering that permeabilities are highest in the extrusive layer. For example, permeability values of ∼10 −13 -10 −11 m 2 have been obtained by matching analytical flow models to heat flow data (Wilcock and McNabb, 1996;Lowell and Germanovich, 2004), values of 3.10 −13 -6.10 −12 m 2 have been derived by modeling flow rate perturbations generated by earthquake swarms at the JdFR Endeavour field (Crone et al, 2010), values of 3.10 −11 -2.10 −14 m 2 have been determined with drill-string packer experiments at the eastern flank of the JdFR (Becker and Fisher, 2000), and values of 10 −13.4 -10 −9.4 m 2 have been obtained by modeling crustal stresses inferred from poroelastically triggered earthquakes at the EPR 9 • 50 N field (Crone et al, 2011). All of these estimates, including ours, were derived by fitting an observable (e.g., phase lag, heat flow, earthquake migration) to a model, such that the accuracy of the parameter estimates depends largely on the model applicability and accuracy.…”

Fluid Phase Separation Processes in Submarine Hydrothermal Systems

“…Although this compositional variability is best indicated by the wide range of dissolved chloride concentrations of vent fl uids that greatly deviate from seawater values (Von Damm et al 1997;Von Damm 2000Seyfried et al 2003), confi rming evidence of phase separation processes can also be traced to the distribution and abundance of dissolved volatiles and other aqueous species known to fractionate between vapor and liquid when seawater phase separation and segregation occurs (Oosting and Von Damm 1996;Berndt and Seyfried 1997;Fornari et al 1998;Butterfi eld et al 1999;Lilley et al 2003;Von Damm et al 2003). Given the nature of magmatic and tectonic processes associated with the formation of the ocean crust at mid-ocean ridges, which can result in high temperatures at low to moderate pressure conditions (Wilcock and McNabb 1996;Bohnenstiehl et al 2004;Van Ark et al 2007), phase separation processes are not surprising, although the rate of change from vapor to liquid dominated systems and the compositional diversity expressed by ridge vent fl uids, remain enigmatic (Sohn et al 1999;Lilley et al 2003;Von Damm et al 2003;Larson et al 2007). …”

Electrochemical techniques and sensors for ocean research

“…Apart from conductimetry for the determination of salinity, see e.g. the conductivity sensor of (Larson et al, 2007) used to measure solution resistance as a proxy for chloride concentration in hot vent waters, electrochemical impedance does not appear to be used in ocean sensing. This is in part due to the fact that variations in electrochemical impedance are not chemically specific thus not suitable for chemical sensing.…”