Question about Equilibrium vs. Fractional Crystallization in alphaMELTS

[liushanke]

Hello everyone,

I'm working with alphaMELTS (via alphamelts_win64.exe on Windows) and I'm having a bit of trouble understanding how to properly run equilibrium crystallization simulations.

With easyMelts, I can easily switch between fractional and equilibrium modes by choosing whether or not to fractionate solid phases (if my understanding is correct). However, I'm unsure how to achieve a true equilibrium mode within the alphamelts_win64.exe interface.

When I select option 8 in the main menu ("Solid phase(s) to change settings for"), I'm presented with options that seem to be primarily related to fractional crystallization:

Suppress all solid phases

Allow all standard solid phases; optionally limit maximum number

Do not fractionate any solid phases

Fractionate all standard solid phases (current)

Change whether residual solid is measured...

Adjust amount of solid fractionated during fractionation...

My understanding is that these options are primarily concerned with controlling fractional crystallization. Is it actually possible to perform a strict equilibrium crystallization simulation using alphamelts_win64.exe on Windows?

While the difference between the two modes may be minor for some magma systems, I'm concerned about the potential for significant discrepancies in certain situations, especially at higher pressures and water contents.

Any guidance on this would be greatly appreciated.

Thanks in advance,

Shanke

[Paula]

It sounds like you have one or more "Mode: fractionate" line(s) in your .melts file. Just delete them all and you'll get perfectly equilibrium crystallization.

[liushanke]

Hi Paula, thanks for your kind reply. I've received it.