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Figure 1: The experimental data for the phase diagram of iron, plus triple point and extrapolation therefrom [ Anderson, 1993, 1994]. The open circles and squares are the shock wave determinations of by radiance measurements. Two vertical bars represent the found from velocity measurements of Brown and McQueen [1986] using shock waves: there is a solid-solid (s-) transition and a solid liquid (s-) transition.

 
Figure 1: Figure 1 continued

The new determinations of Gallagher and Ahrens [1994], shown by X, are redeterminations of the Bass et al. [1990] values of , where the vertical arrow indicates the reduction in . The dashed line dropping from the 190 GPa triple point shows the separation of the phase from the phase. The diamond anvil cell determinations of are shown by solid lines.

 
Figure 2: Four published phase diagrams of iron out to 330 GPa. Figure 2a (top left), from Williams et al. [1991], where the solid circles with error bars are the shock data from Brown and McQueen [1986] where s- and s- are the solid-solid transition and the solid-liquid transition. Here the phase exists at inner core conditions and the shock wave points of Figure 1 are mapped as a field with hatching. Figure 2b (top right) is from Anderson [1994], where the B&M s- transition marks the melting curve and the B&M s- transition
[4]

 
Figure 2: Figure 2 continued

marks the upper triple point. The t.p. shows the beginning of the phase (not hcp or bcc). Anderson [1993] suggested that is fcc. Figure 2c (lower left) is from Saxena et al. [1994]. The B&M s- transition is marked by a t.p.\ where the liquid, , and meet. The B&M s- transition defines the upper melting curve. The phase exists at inner core conditions. Figure 2d (lower right) is from Boehler [1994]. Here includes the phase shown
[4]

 
Figure 2: Figure 2 continued

in Figure 2c. The s- transition of B&M is displaced downward to define the - boundary. The s- transition of B&M is displaced downward from their values and defines Boehler's -liquid boundary. The -liquid boundary defines the outer core's melting curve, and is the phase of the inner core.