thomasw Posted March 14, 2010 Share Posted March 14, 2010 Dear all, in some calculations of activity-activity and activity-temperature diagrams it is pretty useful to set the activity of minerals involved into the set of reactions to a value that is different from 1.0. For example, consider that you work on fluid-rock interaction and want to look at the controls on mineral stability in an hydrothermally altered rock. Now you have analyzed for example the chlorite in this rock by electron microprobe and used some composition-activity model (in the simplest case just configurational energy arising from ideal mixing) to calculate the activity of one end-member that you consider in the activity-activity diagram (e.g., clinochlore in the chlorite). Then in principle it is possible to calculate and plot an activity-activity diagram for exactly this activity (usually a value smaller than unity). I have done this many times with the help of SUPCRT92, a spreadsheet and paper and pencil. Unfortunately, I have not found if and how this could be done in act2 and tact. In principle, this would be a rather simple and straightforward extension of the set of additional constraints that can be set at the bottom of the Basis pane of act2 (the section labelled with: in the presence of ...). Any suggestions? Best regards, Thomas Quote Link to comment Share on other sites More sharing options...
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