Menu
MDOODZ partial melting module — melt model indices, solidus/liquidus parameterizations, melt fraction computation, melt weakening, per-phase melt configuration, kinetic relaxation, and melting scenario examples.
Install with Codex or Claude Copy this prompt, paste it into Codex, Claude, or another assistant, and let it review the skill page and install it for you.
Based on SOC occupation classification
MDOODZ mechanical anisotropy module — director-based fabric tracking, anisotropy factors (δ_n, δ_s), viscous transverse isotropy, ViscosityConciseAniso, finite strain evolution, anisotropic rifting methodology, and anisotropy scenario examples.
MDOODZ performance benchmarking — running benchmarks, interpreting perf.csv, grid scaling studies, thread scaling, comparing machines, and the benchmark.sh script.
Build, compile, and run MDOODZ simulations — CMake configuration, make targets (build, build-dev, run, clean), dependency installation (SuiteSparse, HDF5, BLAS/LAPACK), OpenMP parallelisation, env.cmake setup, and common troubleshooting.
Code-to-physics glossary for MDOODZ — variable names, struct fields, function names mapped to physical meaning, equations, SI units, grid naming conventions, creep mechanism abbreviations, and solver process stages.
Debugging a failing MDOODZ model — the three failure families (CHOLMOD non-positive-definite, Powell-Hestenes non-convergence, first-iteration NaN), the error-string lookup table, the eta-contrast reality, the two anisotropy recipes, the single-variable bisection cookbook, and the known MDLIB anisotropy bugs with their fix commits. Use when a run crashes, won't factor, won't converge, NaNs, or stalls mid-production.
MDOODZ logging system — LOG_INFO/WARN/ERR/DBG/TIME macros, .txt configuration parameters (log_dest, log_level, log_timestamp, log_ts_mode, log_metadata), colored console output, ANSI-stripped log files, phase timing instrumentation, and metadata prefixes.
| name | skill-melting |
| description | MDOODZ partial melting module — melt model indices, solidus/liquidus parameterizations, melt fraction computation, melt weakening, per-phase melt configuration, kinetic relaxation, and melting scenario examples. |
MDOODZ supports pressure-dependent partial melting via parameterized solidus/liquidus curves. Melting is computed per marker using the marker's temperature and pressure. The melt fraction field (X) is stored at cell centres and written to HDF5 as Centers/X.
.txt file)| Parameter | Default | Description |
|---|---|---|
melting | 0 | Enable melting globally (0=off, 1=on) |
force_melt_weak | 0 | Enable melt-induced viscosity weakening (0=off, 1=on) |
melt_weak | 0.0 | Activation volume override for weakening [J/mol] — typical: 30.0 |
.txt PHASE PROPERTIES blocks)| Parameter | Default | Description |
|---|---|---|
melt | 0 | Melt model index (0=off, see table below) |
tau_kin | 0.0 | Kinetic relaxation time constant [s] — 0.0 = instantaneous equilibrium |
melt | Name | Solidus | Liquidus | Latent heat | Reference |
|---|---|---|---|---|---|
| 1 | Simple T-dependent | 600°C + 273 K (fixed) | 1200°C + 273 K (fixed) | 320 kJ/kg | Stüwe (1995) |
| 10 | Crustal/sediment (P-dependent) | P-dependent formula | 1423 + 0.105·P (MPa) | 380 kJ/kg | — |
| 11 | Felsic/crustal (P-dependent) | P-dependent formula | 1262 + 0.09·P (MPa) | 300 kJ/kg | Schenker et al. (2012) |
| 40 | Mantle peridotite (P-dependent) | P-dependent formula | 2073 + 0.114·P (MPa) | 400 kJ/kg | — |
| 41 | Mantle wet olivine (P-dependent) | P-dependent formula | 2073 + 0.114·P (MPa) | 300 kJ/kg | Schenker et al. (2012) |
| Phase type | Recommended melt | Rationale |
|---|---|---|
| Continental crust (e.g., quartzite, anorthite, granite) | 11 | Felsic solidus, Schenker 2012 |
| Sediments | 10 or 11 | Lower solidus than mantle |
| Lithospheric mantle (dry olivine) | 41 | P-dependent peridotite |
| Asthenosphere (wet olivine) | 41 | Same model, wet conditions |
| Diabase / mafic lower crust | 11 | Treated as crustal |
Source: MDLIB/MeltingRoutines.c, function PartialMelting()
Equilibrium melt fraction:
φ_eq = (exp(α·T) − exp(α·T_s)) / (exp(α·T_l) − exp(α·T_s))
where T_s = solidus temperature, T_l = liquidus temperature, both P-dependent.
With kinetic relaxation (tau_kin > 0):
φ = (dt / (τ_k + dt)) · φ_eq + (τ_k / (τ_k + dt)) · φ_0
where φ_0 is the previous melt fraction and τ_k = tau_kin.
Clamped to [0, 1].
When force_melt_weak = 1 and melt_weak > 0, the code overrides the dislocation creep activation volume for melt-bearing phases:
if (model->force_melt_weak == 1) mat->apwl[k] = model->melt_weak;
This effectively reduces viscosity in regions with high melt fraction. The melt_weak value replaces the power-law activation volume (Vpwl), making melt-bearing regions weaker.
Typical value: melt_weak = 30.0 (used in RiftingMelting, RiftingCombinedYield, and other scenarios).
eta_vp (viscoplastic regularisation)When combining melting with plasticity (plast = 1 or plast = 2), eta_vp must be large enough to stabilise the weakened rheology.
| Model scale | Without melting | With melting |
|---|---|---|
| Lithospheric rifting | eta_vp ≥ 1e19 | eta_vp ≥ 2.5e20 |
| Localised chamber | eta_vp ≥ 1e18 | eta_vp ≥ 1e19 |
Stability warning:
eta_vp = 1e19withmelting = 1at lithospheric scale can produce instabilities (negative viscosity, values ~1e60) after ~100 steps. Useeta_vp = 2.5e20or higher.
plast = 2)No special interaction — plast = 2 works with melting. Ensure T_st and eta_vp are set per phase.
### Global (in header of .txt)
melting = 1
force_melt_weak = 1
melt_weak = 30.0
### Per phase
ID = 0 // Continental crust
melt = 11 // Schenker 2012 felsic
ID = 1 // Lithospheric mantle
melt = 41 // Schenker 2012 mantle
ID = 2 // Asthenosphere
melt = 41 // Schenker 2012 mantle
| Scenario | Melt models used | Application |
|---|---|---|
RiftingMelting | 11 (crust), 41 (mantle) | Extension with decompression melting |
RiftingCombinedYield | 11 (crust), 41 (mantle) | Rifting + combined mode-I/II yield |
SubductionMelting | Fluid-released melting | Slab-edge weakening |
TCMagmaticSystem | 10, 11 | Thermo-chemical magmatic evolution |
PressurizedMagmaChamber | — (thermal only) | Pressurised intrusion |
MeltingOverpressure | — | Melting-induced overpressure |
ChristmasTree | Multi-branch | Dike geometry |
MDLIB/MeltingRoutines.cMDLIB/FlowLaws.c (activation volume override)MDLIB/InputOutput.cCenters/X (melt fraction field)