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Teng Deng

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  1. Hello I try to use React to model the water-rock interaction, but I ran in to a problem. First of all, I use SpecE 8 to balance the fluids, and the fluid was produced for Reaction. In React, I use the fluid to react with Abite, Anorthite, Phlogopite, Annite, Muscovite, Quartz, Maxium_Microline, pyrite and Daphinite-14. In the initial fluid (processed by SpecE 8): pH = 4.5, UO2++ = 15.2 mg/kg (component) However, in the Gtplot file produced by React, the initial values are (Rxn progress = 0 ) pH = 4.032, UO2++ = 0.0001326 mg/kg (component in fluid) My question is: Why aren’t they the same (pH and UO2++)? The SpecE 8, React and Gtplot file are seen attached. Best wishes Teng Deng Fluid composition-V2-output to input.sp8 Reaction V10.rea UO2++.gtc pH.gtc
  2. Hello Jia Wang Thanks for your time and patience. I believe your suggestion “Start with a simple system and then build more complexity with it” is quite useful. Following your suggestions, I add the components one by one. (1) At last, I found that swap pyrite with Fe++ would cause the convergence error (see the SpecE8 file “Fig. 16A-V4”). (2) If I give a certain value like 30 ppm for Fe++ as shown in Table 4.1, the convergence error is gone. However, the Cu++ contents are incredibly low (7*e-7 ppm), much lower than the one in Table 4.1. Consequently, I do not think that this model is correct. (see the SpecE8 file “Fig. 16A-V4-no pyrite”) (3) The only reasonable result is that I set 1 ppm and 30 ppm for Cu++ and Fe++ respectively. (see the SpecE8 file “Fig. 16A-V4-no pyrite and chacopyrite”). However, it does not make any sense, since we can not know Cu and Fe values from geochemical analysis in the H2S-rich fluids of this paper. So my questions is: How can I do the three thing at the same time: swap pyrite in, get reasonable results, kick out the convergence error? Fig. 16A-V4.sp8 Fig. 16A-V4-no pyirte and chalcopyrite.sp8 Fig. 16A-V4-no pyirte.sp8
  3. Hello Jia Wang Of course I can balance the reaction with SpecE8 using the data in Table 4.1, since they are the result after processed from the raw data by geochemical analysis. The geochemical results are what I show above. T=145 °C, CH4=300 ppm, Cl-=4.81 mol/kg, Ca2+ =0.5 mol/kg,Mg2+ =0.12 mol/kg, K+=0.1 mol/kg, Na+=3.5 mol/kg By studying phase diagram, we got other key parameters: pH=4.4, log fO2=-57, H2S= 2*10-3 mol/kg In addition, there are also some minerals buffering the fluids. My question is: How can I get the data in Table 4.1 with the chemical analysis? Best wishes Teng Deng
  4. Hello Jia Wang In order to better illustrate my problem, I would like to give more details. I am current reconstruct the modelling in Perry, (2016). If you want to know more details, please see attached. There are several models in this paper, and what I am showing is the first model (reduced-sufur). The fluid initial of this model used by the author is shown in Table 4.1 of the page 155. The paragenesis sequence is shown in Fig.4.4 of the page 141. The minerals of the ore deposit is shown there. In addition, since the fluids have been through sandstones, so they have been buffer by quartz and feldspar. Please note that due to the size limitation of the attached files, I have deleted most pages in the PDF. The remaining part is related to what we are talking about here. Thanks for your patience and time. Best wish Teng Deng Perry, 2016-sent-many pages deleted.pdf
  5. Hello Jia Wang Thanks for your explanation. I have reattached the file. Pb-Zn deposit-initial fluid.sp8
  6. Hello guys As a GWB user to study the fluid rock interaction in hydrothermal ore deposit, one of the most important initial work is to obtain the composition of fluids. Generally, we use LA-ICP-MS analysis to get the chemical composition of ore fluids. But the data have to be processed with SpecE8 before used as the input file for React. However, the processing by SpecE8 is seldom detailed shown in the paper, confusing starters like me a lot. Here I’d like to show a typical example, and wish to get some help. According to microthermometry and LA-ICPMS analysis of fluid inclusions, we got the following conditions: T=145 °C, CH4=300 ppm, Cl-=4.81 mol/kg, Ca2+ =0.5 mol/kg,Mg2+ =0.12 mol/kg, K+=0.1 mol/kg, Na+=3.5 mol/kg By studying phase diagram, we got other key parameters: pH=4.4, log fO2=-57, H2S= 2*10-3 mol/kg Since the deposit contain quartz, feldspar, pyrite, chalcopyrite, sphalerite and galena, we use these minerals to buffer the contents of SiO2(aq), Al3+, Fe2+, Cu2+, Zn2+ and Pb2+ in fluids. In addition, I also use dolomite to balance Ca2+ in the fluids. However, what I got is: Newton-Raphson did not converge after 999 iterations… So, how can I solve such a problem? Pb-Zn deposit-initial fluid.sp8
  7. Thanks very much for telling me that there are input files in the GBRM scripts. It is really helpful. However, even I use the Ch09-SeO4 in the example file. The obtained >L: SeO4-- are 2.465e-7 molality, different from the book (0.49 * 10-3 umol/g, i.e., 4.9 * 10-7 molality) Is it because of my understanding incorrect? Best wishes Teng Deng Ge
  8. I was trying reconstruct the examples in Pages 150-154 of the book Geochemical and Biogeochemical Reaction Modelling (Second Edition). These examples are about absorption and ion exchanges. The results I got are different from those in the book. I have attached the SpecE and database files. Could you please check and give me some help? CaMgNa_Ix.sdat fresh water.sp8 Freundlich-SeO4--.sdat Kd—SeO4-.sdat Langmuir-SeO4--.sdat sea water.sp8 SeO4--Freundlich.sp8 SeO4--Kd.sp8 SeO4--Langmuir.sp8
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