Jeff

Thank you, that seems like a really silly question now! Jeff

Thank you Brian, that was very helpful. I also found a hydrothermal example in the textbook you mentioned - and with a combination of the two answers I solved that problem. I've also had some success with Fe++/Fe+++ kinetics. How would you go about using a kinetic redox reaction at the same time as adding a reactant? For example, can you set up a rate law and then run a simulation where you add 1kg of reactant seawater to the basis every 1 minute, and only allow equilibration over this time? (rather than thermodynamic equilibrium) I'm imagining some sort of loop function where you instruct the program to add 1kg reactant, react for 1 minute, plot the results, and loop. Let me know if you have any ideas! Jeff

By the way, I realise that I will eventually need to apply a kinetic model to this, as allowing each iteration to reach thermodynamic equilibrium isn't appropriate in this context, and time is very important in hydrothermal mixing. Thanks, Jeff

Hi, I'm attempting to using GWB to model the mixing of hydrothermal fluid with seawater. To start with, I am simply mixing a hot, low salinity fluid high in iron and sulfide with an oxic, high salinity, cold fluid. As expected, rhombic sulfur and pyrite saturate very quickly, but the model allows them to stay in the mixture (i think) and they end up re-dissolving. The model then gets stuck in a loop where it can't decide whether to swap Fe(II) for pyrite or visa verca. Is there a way of 'dumping' mineral phases as they form? i.e. in the context of hydrothermal mixing - form solid sulfide structures which do not remain in the package of fluid which we are considering? Thanks, Jeff (i've tried to attach my .rea file) plume mixing 17Nov.rea