TMernagh

Thanks Tom, I think it will definitely be worth me changing the Print Options to print to file for long and complex models that are prone to crashing. I will do this before I try again. I was aware of the problem with overwriting the X1t/X2t modules. Perhaps it would be better to have some type of version stamp on the file or incoprorate a "Save File As" prompt at the end of the run? With thanks, Terry M.

I have been running a geochemical model in X1t for the past 5 weeks only to have it crash when it is 90% complete. This is annoying enough but it will be more annoying if I cannot retreive the results. I can plot the results using Xtplot but the "View Results" button is greyed out. Can anybody tell me if and how I can retreive the results of the modelling and if there is a method to save the results of X1t and X2t models before they have finished all the iterations?

Thanks Tom, I have set up a model using kinetic minerals as you have suggested. I have managed to find most of the rate constants in the short course manual you gave us. Thanks for including them in the notes. However, I think the complexity of the system has beaten me as I still can't get it to converge! Regards, Terry

Thanks Tom, Following from your advice I have created two sets of equilibrium systems in react which convert the original minerals into alteration minerals in equilibrium with the fluid (not exactly what I wanted but it will have to do). One for the sandstone [u into WMC ver 4] and one for the basalt [u into Seigals ver 7] using the thermo.com.V8.Rb+.dat database. Now I would like to set up a heterogeneous mineral distribution in my domain as you have suggested but have again run into the problem of the limited number of components in the Basis. For example in the sandstone I want quartz (for SiO2), muscovite (for Al+++), Hematite (for O2) etc while in the basalt I want grossular (for SiO2), diaspore (for Al+++), andradite (for O2) etc. however you cannot have more than one mineral per element. I do not want to leave out SiO2, Al+++ and O2 from one of the rocks as this will drastically affect the alteration minerals that are formed. I've attached the model I've developed so far.U into Seigals 25C Ver 7.reaU into WMC Ver 4.reaU into WMC + seigals Ver 1.x2t I guess it may be possible to create two models, one for the sandstone and one for the basalt but I would have to manually extract the residual fluid from each iteration of the sandstone model and then manually enter it into the basalt model to simulate fluid flowing from one rock type into the other. Is there a better way to do this? With thanks, Terry M

Thanks Tom, I think I have GWB reading the tables properly now although it is hard to verify this until you have a working model. Also as you have correctly indicated the minerals should be added to the Initial (Basis) species as the Reactants tab will titrate the minerals in small amounts at each iteration which is not what I want to model. However, and we've discussed this before, the problem with doing this is that you can only add one mineral for each element in the Basis set which is a severe limitation when trying to model natural rock compositions. For my model I want to have a sandstone of the following composition: Quartz + K-Feldspar + Albite + Anorthite + Muscovite + Kaolinite + Magnetite + Pyrite and a basalt of the following composition: Albite + Anorthite + Forsterite + Fayalite + Ferrosilite + Diopside + Hedenbergite + Chamosite + Pargasite + Ilmenite + Magnetite so the problem arises when I want to add more than one mineral containing Fe or Al for example (i.e. for Fe: Magnetite + Pyrite + Fayalite + Ferrosilite etc). Although these rocks may be altered this is the composition I would like to react with a fluid. Anyway, I've attached the X2t model that I have developed so far. Another problem I've encountered is that if you do put lots of minerals in the Basis set then you typically get the error message "Initial Soln is too concentrated" when you try to run the model. I can overcome this problem by increasing the water content to 1,000,000 kg but I don't think this is realistic. My final question with the attached model is that I have set up a symmetric 10 x 5 node domain with a high porosity section in the central (y=3) row representing a fault or aquifer. I was expecting a symmetric dispersion of minerals around the central zone but instead most of the precipitation occurred in the lower right hand corner of the domain (i.e. nodes 5,0 to 9,0 and 5,1 to 9,1). Is this caused by the fact that the calculations are done on these nodes before the higher numbered nodes (i.e. 5,4 to 9,4)? quartz 4.txtK feldspar 4.txtU into WMC + Seigals Ver 4.x2talbite 4.txtanorthite 4.txtmuscovite 4.txtforsterite 4.txtmagnetite 4.txtWMC Seigals Porosity.txtU into WMC + Seigals Ver 4.x2t

I am running X2t Release Version 6.0.5 on Windows XP SP2. I am trying to model fluid flow through 2 different rock types - a sandstone and a basalt and need to set up a gridded domain to show the spatial variation of the 2 rock types. For large grids I prefer to set them up in Microsoft Excel in order to make use of their simple copy&paste tools. So I have set up the grids for each mineral in Excel and then saved them as text files. However, when I try to import them into X2t using the Table option in "Reactants" it doesn't work. I've tried saving the files as both Tab Delimited Text and Unicode Text but neither works. Does X2t require the tables is a specific format in order to import them correctly. If so can somebody tell me what the format is? Otherwise can somebody tell me the best way to import a table into X2t?