how to get the degree of partial melting?

[Renqiang Liao]

Hi, everyone

I'm doing the mantle partial melting using pMelts. The results have been outputted normally lablled as "melts.out". But I don't know how to get the information on the degree of partial melting (F). Is it the different liquid mass? Any suggestions would be helpful to me.

Thank you.
Jon

[Renqiang Liao]

Hi, everyone

I run the rhyolite-MELTS v.1.0.x and I saw the results labelled melts.out. But I can't read the informaton on the proportion of fractionanted minerals, just read the total fractionated minerals. Where I can find the information on the proportion of each fractionated mineral.  Any suggestion could helpful to me. Thank you!

Renqiang

[Paula]

Hi,

For the melt fraction, it depends whether you are fractionating liquid or not. If you are not then you can get both the liquid mass (M_L) and solid mass (M_S) from the melts-liquid.tbl file and calculate the current F as M_L/(M_L + M_S). If you are fractionating liquid then the liquid mass reported in melts-liquid.tbl is just for the current P-T increment, so you will need to know the original mass (M₀). Then you can get F as (M₀ - M_S)/M₀.

For fractional crystallization, you can get a good approximation of the fractionated phases from the list of crystallized phases. Note that the output files are written after equilibration but before fractionation. However the proportion of crystallized phases will differ very slightly from what's actually fractionated as a tiny amount, 10^-5 moles, of each phase is retained during fractionation (this stabilizes the calculation as the same phases are good candidates for equilibrium assemblage for the next step).

For either problem I suggest you have a look at the Tools for processing Rhyolite-MELTS GUI output (melts.out and .tbl files) post as both tools mentioned there will make it easier to extract the relevant information.

Best,
Paula