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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.
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Basé sur la classification professionnelle SOC
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)