Latent heat melt: change A1, A2 and A3 parameters

Dear all,

I’m modeling a rifting process with mantle melting (without melt migration) by using Visco Plastic and Latent heat melt material models (ASPECT 2.3.0-pre). I would like to use a different peridotite solidus and therefore I set different A1, A2 and A3 parameters in the input. However, apparently melt still occurs under the default peridotite solidus conditions (i.e. melt occurs at higher temperatures than I set).

I wonder if I’m doing something wrong or there is a problem I don’t understand.

I attach my input file.

Many thanks in advance.
Kind regards,
continental_extension_melt2.prm (11.0 KB)

Hi Manuel,

One possible problem could be this: If compositional fields are specified, the latent heat melt model assumes that the first compositional field is the fraction of pyroxenite and the rest of the material is peridotite (see also the documentation of that model). You do have compositional fields, so your first field (seed) is assumed to be pyroxenite, and will start melting at lower temperatures. This is not ideal, but we haven’t gotten to fixing it yet (also because changing it would not be backwards compatible).

Looking at your model setup: It looks like you don’t want to include latent heat in your model (it is switched off in the heating terms). In that case, melting would only be a postprocessing step in your models. If that’s true, you can use the “melt fraction” postprocessor instead of using the latent heat melt material model. The postprocessor only computes the pyroxenite melting if there is actually a field called “pyroxenite” in the simulation.

Best regards,

Dear Juliane,

many thanks for your reply!
I think the use of postprocessor only looks fine with me. I actually imposed seed as first compositional field just to limit the melting of pyroxenite (otherwise the whole mantle would be treated as pyroxenite). But at this stage I’m only interesting in tracking potential conditions for mantle melting, therefore I use post processor only.