Melt extraction

Several models relating the isotopic effects of U-series disequilibria to the timescales of the melting process have now been proposed (e.g., McKenzie 1985 Williams and Gill 1989 Spiegelman and Elliott 1993 Qin 1992 Iwamori 1994 Richardson and McKenzie 1994). While these models differ mainly in their treatment of the melt extraction process (i.e., reactive porous flow vs near fractional melting), because they incorporate the effect... 

Ribe NM Smooke MD (1987) A stagnation point flow model for melt extraction from a mantle plume. J Geophys Res 92 6437-6443... 

Spiegelman M, McKenzie D (1987) Simple 2-D models for melt extraction at mid-ocean ridges and island arcs. Earth Planet Sci Lett 83 137-152... 

Woodhead J, Eggins S, Gamble J (1993) High field strength and transition element systematics in island arc and back-arc basin basalts evidence for multi-phase melt extraction and a depleted mantle wedge. Earth Planet Sci Lett 114 491-504... 

At each step, a fraction of fluid f is added to the mantle wedge from the slab. The bulk partition coefficients used for fluid dehydration can be derived from published mineral/fluid partition coefficients (see Tables Al and A2). The composition of the residual slab is estimated as follows after At which is the time step between two melt extractions (similar equation for Th and Pa) ... 

We assume that a constant mass fraction fr remains in the mantle wedge after melt extraction. As in Section A2 of the Appendix, the ratio of slab mass to wedge mass is assumed to be equal to 1 but more complex models are also possible. The bulk composition of the mantle wedge after melt extraction is calculated with the following equation after each extraction increment ... 

Nicolas, A. (1986). A melt extraction model based on structural studies in mantle peridotites. J. Petrol., 27, 999-1022. 

By substituting D = 0.02 and (Z> = 0.01 into Eq. (3.6), we can obtain the source-normalized concentration in the extracted melt C/Cgas a function of X. The results are plotted in Fig. 3.1. Similarly, substituting Z) = 0.02 and (Z> = 0.01 into Eq. (3.7), we can obtain the source normalized concentration in the residual melt C /Cg as a function of X. The results are also plotted in Fig. 3.1. Note that after melt extraction begins, residual melt is more depleted in incompatible elements than the extracted melt. At about 15% of melting, the residual melt does not contain much incompatible elements. 

Chapters 1 to 3 consider melting and melt extraction. In this chapter, we further take into account input of materials into the melting zone. 

According to Eq. (4.25), the initial condition when the melting extraction starts is... 

The Meanings of melting rate and melt extraction rate... 

Activity ratios in the melt when / < before melt extraction starts... 

It was obtd when phenyl cyanide p-nitro-benzhydrazide benzene sulfonate were heated at 200° for 3 hrs, cooled the crystalline melt extracted with cold NaOH soln the extract acidified with coned HO (Ref 2) and by other methods (Refs 3, 4, 6 8)... 

Tellurium occurs chiefly as telluride in gold, silver, copper, lead, and nickel ores in Colorado. California, Ontario, Mexico, and Peru, and infrequently as free tellurium and tellurite (tellurium dioxide, Te02) The anode mud from copper and lead refineries, or the flue dust from roasting telluride gold ores is treated by fusion with sodium nitrate and carbonate and the melt extracted with water. The resulting solution is acidified carefully with H2S04, whereupon tellurium dioxide is precipitated, and die dioxide reduced to free tellurium by heating with carbon. 

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