Appendix Table 5: Parameters for mixing curves in Fig. 1c.

	SiO2 wt%	3He/4He Ra	He abundances cm3 STP/g	
			curve a	curve b	curve c	
mantle melta	49.0	8.0	3 *10-4	3 *10-4	3 *10-4	
crustal componentb	69.0	0.1	1.16 *102	3.87* 10-4	3.0*10-5	

a:	He abundances in mantle melt is equivalent to 5% melt from MORB source with He =1.5*10-5 cm3 STP/g (Allegre et al., 1986/1987, Sarda & Graham, 1990) and assuming perfect incompatibility of He during melting.
b:	crustal component calculated with U=0.633 ppm and Th= 3.06 ppm from MVB crustal xenoliths (Ruiz et al., 1988b; Roberts and Ruiz, 1989; Schaaf et al., 1994; Lawlor et al., 1999; Gomez-Tuena et al., 2003; Martinez-Serrano et al., 2004; Ortega-Gutiérrez et al., 2011).