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Mineral phases available in MELTS, pMELTS and pHMELTS.

Started by Paula, September 18, 2009, 01:52:19 PM

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Paula

September 18, 2009, 01:52:19 PM Last Edit: August 18, 2017, 10:18:41 AM by Paula
A list of possible mineral phases that can be stabilised in the MELTS family of algorithms was requested ages ago (when I was on leave) and I totally forgot until now. So sorry for the delay in getting round to it...

The available solid solution phases and their end-members are listed below, in the order in which they are usually output. The solution models are exactly the same in the MELTS and pMELTS models (and therefore also in pHMELTS, which is based on pMELTS). For the relevant references see here and here. Some of the end-member thermodynamic data differ slightly between MELTS and pMELTS, as described in Ghiorso et al., 2002.

Quote
  • olivine
    tephroiteMn2SiO4
    fayaliteFe2+2SiO4
    Co-olivineCo2SiO4
    Ni-olivineNi2SiO4
    monticelliteCaMgSiO4
    forsteriteMg2SiO4
  • garnet
    almandineFe2+3Al2Si3O12
    grossularCa3Al3Si3O12
    pyropeMg3Al2Si3O12
  • melilite
    akermaniteCa2MgSi2O7
    gehleniteCa2Al2SiO7
    Fe-akermaniteCa2Fe2+Si2O7
    soda-meliliteNa2Si3O7
  • orthopyroxene (see note *; see note |)
    diopsideCaMgSi2O6
    clinoenstatiteMg2Si2O6
    hedenbergiteCaFe2+Si2O6
    alumino-buffoniteCaTi0.5Mg0.5AlSiO6
    buffoniteCaTi0.5Mg0.5Fe3+SiO6
    esseniteCaFe3+AlSiO6
    jadeiteNaAlSi2O6
  • clinopyroxene (see note *; see note |)
    diopsideCaMgSi2O6
    clinoenstatiteMg2Si2O6
    hedenbergiteCaFe2+Si2O6
    alumino-buffoniteCaTi0.5Mg0.5AlSiO6
    buffoniteCaTi0.5Mg0.5Fe3+SiO6
    esseniteCaFe3+AlSiO6
    jadeiteNaAlSi2O6
  • cummingtonite
    cummingtoniteMg7Si8O22(OH)2
    gruneriteFe2+7Si8O22(OH)2
  • clinoamphibole (see note *)
    cummingtoniteMg7Si8O22(OH)2
    gruneriteFe2+7Si8O22(OH)2
    tremoliteCa2Mg5Si8O22(OH)2
  • orthoamphibole (see note *)
    cummingtoniteMg7Si8O22(OH)2
    gruneriteFe2+7Si8O22(OH)2
    tremoliteCa2Mg5Si8O22(OH)2
  • hornblende
    pargasiteNaCa2Mg4AlAl2Si6O22(OH)2
    ferropargasiteNaCa2Fe2+4AlAl2Si6O22(OH)2
    magnesiohastingsiteNaCa2Mg4Fe3+Al2Si6O22(OH)2
  • biotite
    anniteKFe2+3Si3AlO10(OH)2
    phlogopiteKMg3Si3AlO10(OH)2
  • feldspar
    albiteNaAlSi3O8
    anorthiteCaAl2Si2O8
    sanidineKAlSi3O8
  • nepheline
    na-nephelineNa4Al4Si4O16
    k-nephelineK4Al4Si4O16
    vc-nephelineNa3Al3Si5O16
    ca-nephelineCaNa2Al4Si4O16
  • kalsilite
    na-nephelineNa4Al4Si4O16
    k-nephelineK4Al4Si4O16
    vc-nephelineNa3Al3Si5O16
    ca-nephelineCaNa2Al4Si4O16
  • leucite
    leuciteKAlSi2O6
    analcimeNaAlSi2O5(OH)2
    na-leuciteNaAlSi2O6
  • spinel
    chromiteFe2+Cr2O4
    hercyniteFe2+Al2O4
    magnetiteFe2+Fe3+2O4
    spinelMgAl2O4
    ulvospinelFe2+2TiO4
  • rhm-oxide
    giekeliteMgTiO3
    hematiteFe3+O3
    ilmeniteFe2+TiO3
    pyrophaniteMnTiO3
  • ortho-oxide
    psuedobrookiteFe3+2TiO5
    ferropseudobrookiteFe2+Ti2O5
    karrooiteMgTi2O5
  • alloy-solid
    Fe-metalFe
    Ni-metalNi
  • alloy-liquid
    Fe-liquidFe
    Ni-liquidNi

* Note that in some MELTS software there is just one amphibole solid solution, rather than separate clino- and ortho- phases. Also, early releases of MELTS (e.g. prior to the development of the pMELTS algorithm) had a phase called 'pyroxene'. Although all current versions of MELTS have 'clinopyroxene' and 'orthopyroxene' you may see 'pyroxene' in some older documentation.

| Note that the compositions of the essenite, buffonite and alumino-buffonite end members mean that calculations for bulk compositions that contain just two of Fe2O3, TiO2 and Al2O3 are likely to fail (e.g. no TiO2 in the bulk requires that buffonite and alumino-buffonite cancel out exactly).

Although the solution models are the same in all the algorithms, the names of a few solid solutions differ between MELTS and pMELTS when using the graphical user interfaces (i.e. standalone MELTS, CORBA MELTS or Java MELTS):

Quote

MELTS namepMELTS name
nephelinenepheline ss
leuciteleucite ss
kalcilitekalcilite ss
ortho-oxideortho oxide
rhm-oxiderhm oxide

Note: alphaMELTS (and adiabat_1ph) can accept either form in files - its input routine replaces spaces or hyphens within phase names with underscores, before making any string comparisons. When entering phase names at the menu prompt (e.g. for phase diagram mode) use the MELTS form to avoid problems with spaces.

Note also: early releases of MELTS (e.g. prior to the development of the pMELTS algorithm) used what are now the pMELTS names so that the input file that accompanies this old tutorial will cause read errors if used in the current graphical user interfaces without modification.

The pure phases included in all versions of MELTS and pMELTS are shown below (the phases in brackets are the ones that appear immediately before and after, in case you are trying to anticipate the output order):

Quote

spheneCaTiSiO5(olivine; garnet)
aenigmatiteNa2Fe5TiSi6O20(clinopyroxene; cummingtonite)
muscoviteKAl2Si3AlO10(OH)2(biotite; feldspar)
quartzSiO2(feldspar; tridymite)
tridymiteSiO2(quartz; cristobalite)
cristobaliteSiO2(tridymite; nepheline)
corundumAl2O3(leucite; rutile)
rutileTiO2(corundum; perovskite)
perovskiteCaTiO3(rutile; spinel)
whitlockiteCa3(PO4)2(ortho-oxide; apatite)
apatiteCa4(PO4)3(OH)(whitlockite; water)
waterH2O(apatite; alloy-solid)

alphaMELTS (and adiabat_1ph) has these extra pure phases, as they are needed for the pHMELTS model. They all appear at the end of the output list:

Quote

andalusiteAl2SiO5
sillimaniteAl2SiO5
kyaniteAl2SiO5
coesiteSiO2
talcMg3Si4O10(OH)2
anthophylliteMg7Si8O22(OH)2
cordieriteMg2Sl4SI5O18
lawsoniteCaAl2Si2O6(OH)4
antigoriteMg48Si34O85(OH)62
chrysotileMg3Si2O5(OH)4
bruciteMg(OH)2

Hope that helps.  If you spot any errors or omissions please let me know.

Paula

Paula

#2
May 28, 2021, 04:58:17 PM
There is pure Al6Si2O13 mullite in the Berman (1988) dataset. I can add that to the next alphaMELTS 2 / alphaMELTS for MATLAB/Python releases (coming in the next few weeks) if it will help.

However, natural mullites are rather variable in composition. Without accounting for the excess Al2O3, it is likely that mullite stability in MELTS will be underestimated. We were vaguely thinking about adding a mullite solid solution model a while back - before Covid - so I suppose we could revisit that idea. It would require at least one ordering parameter, so not completely trivial to implement.

We are busy with the upcoming alphaMELTS 2 workshop (https://magmasource.caltech.edu/workshops/goldschmidt/) and I have other things lined up for July / early August. But if you give me a little more information on what you're trying to model I'll consider putting mullite ss on the to-do list for after that!

Paula
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