Abstract
Reversed phase equilibrium experiments in the system (Ca, Mg, Fe)2SiO4 provide four tielines at P≪1 bar and 1 kbar and 800° C–1,100° C. These tielines have been used to model the solution properties of the olivine quadrilateral following the methods described by Davidson et al. (1981) for quadrilateral clinopyroxenes. The discrepancy between the calculated phase relations and the experimentally determined tielines is within the uncertainty of the experiments. The solution properties of quadrilateral olivines can be described by a non-convergent site-disorder model that allows for complete partitioning of Ca on the M2 site, highly disordered Fe-Mg cation distributions and limited miscibility between high-Ca and low-Ca olivines. The ternary data presented in this paper together with binary solution models for the joins Fo-Mo and Fa-Kst have been used to evaluate two solution parameters:
.
Ternary phase quilibrium data for olivines tightly constrain the value of F0, but not that for ΔG 0* which describes nonideality in Fe-Mg mixing. From this analysis, we infer a function for the apparent standard state energy of Kst:
where T is in Kelvins and the 298 K value is relative to oxides.
Similar content being viewed by others
Abbreviations
- t :
-
X FeM2 −X FeM1
- X :
-
XFo
- Y :
-
\(X_{Ca_2 SiO_4 } \)
- ΔG 0E :
-
μ 0M1M2FeMg −μ 0M1M2MgFe
- ΔG *0 :
-
μ 0M1M2MgFe +μ 0M1M2FeMg −μ 0M1M2MgMg −μ 0M1M2FeFe
- F 0 :
-
2(μ 0M1M2MgCa −μ 0M1M2FeCa +μ 0M1M2FeFe −μ 0M1M2MgMg
- \(\mu _{Mg\overline {Fe} SiO_4 }^0 \) :
-
μ 0M1M2−MgMg μ 0M1M2−FeFe
- \(\mu _{Ca\overline {Fe} SiO_4 }^0 \) :
-
μ 0M1M2−CaCa −μ 0M1M2−FeFe
- W FeCa :
-
μ 0M2M2FeCa −μ 0M2M2FeFe -μ 0M2M2CaCa
- W MgCa :
-
μ 0M2M2MgCa −μ 0M2M2MgMg -μ 0M2M2CaCa
- μ 0M1M2FeCa :
-
μ 0Kst
- μ 0M1M2MgCa :
-
μ 0Mo
- μ 0M1M2FeFe :
-
μ 0Fa
- μ 0M1M2MgMg :
-
μ 0Fo
- μ 0 M1M2CaCa :
-
\(\mu _{Ca_2 SiO_4 }^0 \)
References
Andersen DJ, Lindsley DH (1979) The olivine-ilmenite thermometer. Proc 10th Lunar and Planet Sci Conf, pp 493–507
Andersen DJ, Lindsley DH (1981) A valid Margules formulation for an asymmetric ternary solution: revision of the olivine-ilmenite thermometer, with applications. Geochim Cosmochim Acta 45:847–853
Bartholomew PR (1982) Fe-Mg solution properties for olivine from ion exchange experiments (abstr). Geol Soc Am Progr 14:439
Biggar GM, O'Hara MJ (1969) Monticellite and forsterite crystalline solutions. J Am Ceram Soc 52:249–252
Bowen NL, Schairer JF (1935) The system MgO-FeO-SiO2. Am J Sci 29:151–217
Burns RG (1970) Mineralogical Applications of Crystal Field Theory. Cambridge University Press, Cambridge
Brown GE Jr (1980) Olivines and silicate spinels. In: PH Ribbe (ed), Vol. 5 Reviews in Mineralogy, pp 275–381. Mineral Soc, Washington, DC
Davidson PM, Lindsley DH (1982) Nonconvergent solution model for quadrilateral pyroxenes (Quad Cpx) (abstr). EOS 63:465
Davidson PM, Lindsley DH, Grove TL (1981) Ca-Mg-Fe clinopyroxene: a solution model (abstr). EOS 62:412
Davidson PM, Grover J, Lindsley DH (1982) (Ca, Mg)2Si2O6 clinopyroxenes: A solution model based on nonconvergent sitedisorder. Contrib Mineral Petrol 80:88–102
Engi M (1980) The solution behaviour of olivine in the temperature range from 500K to 1500K (abstr). Geol Soc Am Abstr Progr 12:421
Fisher GW, Medaris LG (1969) Cell dimensions and X-ray determinative curve for synthetic Mg-Fe olivines. Am Mineral 54:741–753
Ghose S (1982) Order-disorder in ferromagnesian silicates. I. Crystal chemistry. In: Advances in physical geochemistry, Vol 2, pp 4–57. Springer-Verlag, Berlin, Heidelberg, New York
Helgeson HC, Delany JM, Nesbit HW, Bird DK (1978) Summary and critique of the thermodynamic properties of rock-forming minerals. Am J Sci 278 A: 1–229
Kawasaki T, Matsui Y (1977) Partitioning of Fe2+ and Mg2+ between olivine and garnet. Earth Planet Sci Lett 37:159–166
Kitayama K, Katsura T (1968) Activity measurements in orthosilicate and metasilicate solid solutions. I. Mg2SiO4-Fe2SiO4 and MgSiO3-FeSiO3 at 1204° C. Bull Chem Soc Japan 41:1146–1151
Larimer JW (1968) Experimental studies in the system Fe-MgOSiO2-O2 and their bearing on the petrology of chondritic meteorites. Geochim Cosmochim Acta 32:1187–1207
Lumpkin GR, Ribbe PE, Lumpkin NE (1983) Compositions, order-disorder and lattice parameters of olivines: Determinative methods for Mg-Mn and Mg-Ca silicate olivines. Am Mineral 68:1174–1182
Matsui Y, Nishizawa O (1974) Iron(II)-magnesium exchange between olivine and calcium-free pyroxene over a temperature range 800° C to 1300° C. Bull Soc Fr Mineral Crystallogr 97:122–130
Mukhopadhyay DK, Lindsley DH (1982) Reconnaissance study on the extent of solid solution in Ca-Mg-Fe olivines. (abstr). Geol Soc Am Abstr Progr 14:572
Mukhopadhyay DK, Lindsley DH (1983) Phase relations in the join kirschteinite (CaFeSiO4) — fayalite (Fe2SiO4. Am Mineral 68:1089–1094
Nafziger RH, Muan A (1967) Equilibrium phase compositions and thermodynamic properties of olivines and pyroxenes in the system MgO-“FeO”-SiO2. Am Mineral 52:1364–1385
O'Neill H St C, Wood BJ (1979) An experimental study of Fe-Mg partitioning between garnet and olivine and its calibration as a geothermometer. Contrib Mineral Petrol 70:59–70
Papike JJ, Cameron M (1976) Crystal chemistry of silicate minerals of geophysical interest. Rev Geophys Space Phys 14:37–80
Sack RO (1980) Some constraints on the thermodynamic mixing properties of Fe-Mg orthopyroxenes and olivines. Contrib Mineral Petrol 71:257–269
Sack RO (1982) Spinels as petrogenetic indicators: Activity-composition relations at low pressures. Contrib Mineral Petrol 79:169–186
Schairer JF, Osborn EF (1950) The system CaO-MgO-FeOSiO2: I. Preliminary data on the join CaSiO3-MgO-FeO. J Am Ceram Soc 33:160–167
Simkin T, Smith JV (1970) Minor-element distribution in olivine. J Geol 78:304–325
Thierry P, Chatillon-Colinet C, Mathieu JC, Regnard JR, Amosse J (1980) Thermodynamic properties of the forsterite-fayalite (Mg2SiO4-Fe2SiO4) solid solution. Determination of heat of formation. Phys Chem Minerals 7:43–46
Thompson JB Jr (1969) Chemical reactions in crystals. Am Mineral 54:341–375
Thompson JB Jr (1970) Chemical reactions in crystals: Corrections and clarification. Am Mineral 55:528–532
Warner RD, Luth WC (1973) Two-phase data for the joins monticellite (CaMgSiO4) — forsterite (Mg2SiO4): Experimental results and numerical analysis. Am Mineral 56:998–1008
Williams RJ (1971) Reaction constants in the system Fe-MgO-SiO2-O2 at 1 atm between 900° and 1300°: Experimental results. Am J Sci 270:334–360
Williams, RJ (1972) Activity-composition relations in the fayaliteforsterite solid solution between 900° C and 1300° C at low pressures. Earth Planet Sci Lett 15:296–300
Wood BJ, Kleppa OJ (1981) Thermochemistry of forsterite-fayalite olivine solutions. Geochim Cosmochim Acta 45:529–534
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Davidson, P.M., Mukhopadhyay, D.K. Ca-Fe-Mg olivines: phase relations and a solution model. Contr. Mineral. and Petrol. 86, 256–263 (1984). https://doi.org/10.1007/BF00373671
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00373671