Ken

oops... Actually I just realized it is not pH that I should be interested in but calcite solubility

Hey I have just opened GWB-standard (v7) for the first time and wondered if anyone could help me with what is probably a very simple exercise (I apologize in advance for ignorance). I am trying to make plots of the change in pH of a model CO2 bearing aqueous hydrothermal fluid as it cools at different pressures. I am interested to see if there are any "cliffs" in pH. The details on the fluid and the system are as follows aqueous fluid cooling from 300C to 150C pressure could have been anywhere from 200 - 700 bars CO2 = 2 - 4 mol% CH4 = 0.2 - 2.3 mol% H2S = 0.01 - 0.2 mol% NaCl = 2 - 4 wt% the fluid also contained He and the following trace elements Sb, Hg, As, Au, Ag, Te, Tl, Rb, W, Cu, There was also Si (enough to become saturated in quartz as it cools below 200C), Ca, K in the fluid Could give me pointers on how to produce plots of T vs pH for my model fluid as it cools (for a range of pressures and CO2 contents)? Thanks Ken