Table 2 List of input parameters of model runs. LP runs simulate isothermal closed system ascent of LP magmas (melt composition data Métrich et al., 2010) within their storage zone (300– 190 MPa pressure range), and upon shallow emplacement (down to 100 MPa). Redox conditions along the decompression path were fixed by the Fe2+/Fe3+ buffer, for which we adopted the value of 3.4. This choice is based on XANES determinations on a hydrous (H2O=2.9 wt.%) LP magma melt inclusion (Bonnin-Mosbah et al., 2001), but is also consistent with the olivine-liquid iron and magnesium partition observed in a large set of Stromboli MIs (Bertagnini et al., 2003). The resulting logfO2 conditions range from 0.07 to 0.82 NNO (NNO is the Nickel–Nickel Oxide buffer). Note that while MI compositions can be taken as good proxies for total (exsolved+dissolved) water and sulphur contents (then evaluated as H2OTOT: 3.4 wt.%; STOT: 0.16 wt.%, respectively), LP magmas were probably already saturated with a CO2-rich gas phase when the most primitive MIs formed. If such, the highest measured dissolved CO2 content (∼0.2 wt.%; see Fig. 7a) in MIs would significantly underestimate CO2TOT. Four separate LP runs (with different CO2TOT contents; these should be viewed as CO2 concentrations in the magma, i.e., in the melt plus gas suspension) were thus carried out. As for HP runs, we considered a shoshonitic melt with total CO2, H2O, and S contents of 0.04, 1.2 and 0.1 wt.%, respectively (as from representative compositions of MIs in olivines from erupted HP products; Métrich et al., 2010). The recurrent observation of a sulphide immiscible liquid phase in MIs suggests that the HP magma is potentially in a more reducing redox state than the LP magma; we therefore performed model runs at both NNO at NNO-1 redox conditions. For both LP and HP runs, melt composition data are from Métrich et al. (2010).
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