Dynamic melting

Pickett et al. 1997) in MORE samples played an important role, not only to address the problem of magma transfer times, but also in the development of dynamic melting models able to sustain such disequilibria over long periods. In subduction zone volcanoes, the combined study of and Ra- °Th disequilibria place unique constraints on the... 

Both dynamic melting and equilibrium transport melting require that the porosity when two nuclides are fractionated from one another is similar to the size of the larger of the partition coefficients for the two nuclides. Given the low values of the experimental determinations of Du and Dxh, the porosities required to explain the observational data in these models are generally less than 0.5% and often times closer to 0.1%. Such low porosity estimates have been criticized based on physical grounds given the low estimated mantle permeability derived from the extent of melt connection observed in experiments (Paul 2001). 

Dynamic melting models provide results that are similar to those obtained from the chromatographic porous flow melting model in that the extent of ( Ra/ Th)... 

Analytical solutions for disequilibria during dynamic melting (near... 

Figure 15. (a) Comparison of equilibrium porous flow (EPF Spiegelman and Elliott 1993) and dynamic melting (DM Williams and Gill 1989) models for Ra- °Th and activity ratios in... 

Lindt, J. T., A Dynamic Melting Model for a Single-Screw Extruder, Polym. Eng. ScL, 16, 284 (1976)... 

Fig. 1.1. A sample diagram showing batch, fractional and dynamic melting models. Filled circles represent melts in equilibrium with the residual solid. There is no residual melt for the fractional melting model.

It is noted that the relationship between X and F is also important to distinguish the dynamic melting model from both the batch melting and the fractional melting models (Fig. 3). 

---