caa a22 4500 465791751 CHVBK 20180323112026.0 cr unu---uuuuu 170327e19901001xx s 000 0 eng 10.1007/BF00302495 doi (NATIONALLICENCE)springer-10.1007/BF00302495 Fe-Zn mixing energetics of the Iss phase in the system Cu-Fe-Zn-S [Elektronische Daten] [B. Mishra, M. Panigrahi] A thermodynamic analysis of the intermediate solid solution (Iss) of near-cubanite composition has been attempted by considering an Fe−Zn exchange equilibrium between Iss and sphalerite. The interchange free-energy parameter of Fe−Zn mixing in Iss (WIss) and the free energy of the exchange equilibrium (ΔG1,T ) have been deduced at 500, 600, 700 and 723° C using the compositional data of sphalerite and Iss from phase equilibrium experiments and by the standard method of linear regression analysis. For sphalerite, two independent activity-composition models have been chosen. The extracted values of ΔG1,T and WIss, using both models, are compared. Although the values match, the errors in the extracted parameters are relatively larger when Hutcheon's model is used. Both ΔG1,T and WIss show linear variations with temperature, as given by the following relations: ΔG1,T = −35.41 + 0.033 T in kcal (SE=0.229)WISS= 48.451 − 0.041 T in kcal (SE=0.565) Activity-composition relations and different mixing parameters have been calculated for the Iss phase. A large positive deviation from ideality is observed in Iss on the join CuFe2S3−CuZn2S3. No geothermometric application has been attempted in this study, even though Iss of cubanite composition (isocubanite) in association with sphalerite, pyrite and pyrrhotite is reported from seafloor hydrothermal deposits. This is due to the fact that: (a) the temperatures of formation of these deposits are significantly lower than 500° C, the lower limit of appropriate experimental data base; (b) microprobe data of the coexisting isocubanite and sphalerite in the relevant natural assemblages are not available. Springer-Verlag, 1990 Mishra B. Department of Geology and Geophysics, Indian Institute of Technology, 721302, Kharagpur, India aut Panigrahi M. Department of Geology and Geophysics, Indian Institute of Technology, 721302, Kharagpur, India aut Contributions to Mineralogy and Petrology Springer-Verlag 105/5(1990-10-01), 562-568 0010-7999 105:5<562 1990 105 410 https://doi.org/10.1007/BF00302495 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00302495 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Mishra B. Department of Geology and Geophysics, Indian Institute of Technology, 721302, Kharagpur, India aut NATIONALLICENCE 700 1- Panigrahi M. Department of Geology and Geophysics, Indian Institute of Technology, 721302, Kharagpur, India aut NATIONALLICENCE 773 0- Contributions to Mineralogy and Petrology Springer-Verlag 105/5(1990-10-01), 562-568 0010-7999 105:5<562 1990 105 410 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer