Figure 4

Modeled melt Cl/F ratios are shown as a function of degrees of fluid induced melting. Model tests three slab components (stars): slab fluid composition from Straub and Layne ([2003]) (black star), slab fluid composition from Le Voyer et al. ([2010]) (grey star), and slab melt composition from Le Voyer et al. ([2010]) (white star). Lines exhibit the variation of the rate of fluid-induced melting, by changing α values: 0.026 (dashed lines), 0.049 (dotted lines), and 0.059 (solid lines). Crosses are calculated points from the model joined by the lines for more clarity. The black diamond shows the depleted mantle composition. The grey rectangle on the side of the diagram shows the range of Cl/F in arc melt inclusions (Straub and Layne [2003]; Elburg et al. [2006]; Wysoczanski et al. [2006]; Churikova et al. [2007]; Portnyagin et al. [2007]; Sadofsky et al. [2008]; Vigouroux et al. [2008]; Bouvier et al. [2008]; [2010]; Le Voyer et al. [2008]; [2010]; Sorbadere et al. [2011]; Shaw et al. [2012]; Rose-Koga et al. [2012]). The Cl/F ratio is determined by the slab component, the degree of melting, but also the rate of fluid-induced melting. In other words, it means that the amount of fluid component has an influence of the Cl/F ratio in melts. Interestingly, at low degrees of slab fluid-induced melting (1% to 10%), Cl/F ratios in melts are higher for α = 0.049 than for α = 0.059. This is because Cl content in the melt is controlled by increasing incompatibility in opx and the dissolution of opx with increasing α.