Fig. 6. Plots of Cl/(Cl+F) vs. Mg/(Mg+Fe) for primary fluorapatite and biotite in sample 121401E, including data from Grew et al. (2006) . (a) Fluorapatite. Numbers in legend refer to section; C indicates spots near chopinite, W indicates spots near wagnerite. (b) Numbers in legend refer

Fig. 3. Photomicrograph of fluorapatite segregation (Ap) containing four grains of chopinite (numbered, Fig. 4 ) in section 121401E4. Matrix is quartz (Qz); Bt 1 and 2 – biotite grains closest to chopinite (Table 9 ); only a tip of the second grain is visible in this photograph. Plane polarized

F igure 11. Mg/Fe ratios of coexisting chladniite and sarcopside-chopinite in GRA95209 (GRA) and terrestrial (Terra) occurrences ( a ) and between chladniite and farringtonite in GRA95209 ( b ). ( a ) K D = (Mg/Fe) Src /(Mg/Fe) Cld ; R 2 = 0.936 for least-squares fit to sarcopside

Fig. 10. Schematic pressure-temperature diagram showing isopleths calculated from the reaction and volume change in the Mg 3 (PO 4 ) 2 system (Chp 1-Far 1, Brunet & Vielzeuf 1996 ; Brunet et al. 1998 ) for chopinite-sarcopside solid solution associated with farringtonite solid solution

( Ericsson et al. 1986 ), Mg-Fe sarcopside at 500–800 bars, 300–650°C ( Charalampides et al. 1988 ), Fe-Mg chopinite at 30 kbar, 600°C ( Annersten and Nord 1980 ), and graftonite at 1 bar, 800°C ( Nord and Ericsson 1982a , 1982b) . Fields for individual minerals: Far = farringtonite, Chp = chopinite, Grf

in composition to grains so characterized. However, the identity of one composition (queried farringtonite) is richer in Fe than other farringtonite. Data for type chopinite and terrestrial compositions are from Grew et al. (2007) supplemented by analyses of sarcopside and graftonite in a sample from the Bull

F igure 2. ( a ) Kikuchi pattern for chopinite section PTS, 40, area 1-2b. The numbers on the image are Miller indices for the poles at the intersection of the bands, which are produced by specific sets of crystallographic planes. The mean angular deviations for the match ( b ) are 0.536

Fig. 1. Projection of the chopinite structure along b . M2 octahedra (Mg enriched) form unbroken edge-sharing chains parallel to a , whereas M1 octahedra (Fe enriched) alternate with vacant polyhedra (dark with line and cross pattern). PO 4 tetrahedra are marked with crosses.

Fig. 2. Plot of natural farringtonite, graftonite, sarcopside, and chopinite compositions in terms of the divalent cations excluding Ca. The fields for terrestrial graftonite (dashed line) and sarcopside (solid line) are largely from intergrowths ( Černý et al. , 1998 ; Corbella i Cordomí

Fig. 4. Chopinite (Cpn) enclosed in fluorapatite (Ap) in section 121401E4. (a) Photomicrograph of grain 1. Plane polarized light. (b) Back scattered electron image of this grain. (c) Photomicrograph of grain 3. Plane polarized light. (d) Back scattered electron image of this grain. (e) Back

and sarcopside, PTS, 39, area 1–3 (cf. rectangle in Fig. 4b ). ( d ) Sarcopside with pitted surface surrounded by rim of chladniite, containing plates of graphite, PTS, 39, area 1–4. ( e ) Three-phase phosphate assemblage, PTS, 39, area 2-1. ( f ) Chopinite (confirmed with EBSD, Table 1 , analysis Table 6

F igure 12. Mn/Fe ratios of coexisting chladniite-johnsomervilleite (Jhn), sarcopside (Src)-chopinite, graftonite (Grf) and farringtonite in GRA95209 (this study), terrestrial occurrences (Terra; sources are given in caption for Fig. 11 ) and IIIAB iron meteorites ( Olsen et al. 1999 ). Lines

F igure 13. Isopleths calculated from the experimentally determined reaction and volume change in the Mg 3 (PO 4 ) 2 system (solid line) for end-member chopinite and farringtonite ( Brunet and Vielzeuf 1996 ; Brunet et al. 1998 ) assuming ideal solid solution for both minerals ( Grew et al

) Photomicrograph of sapphirine in direct contact with quartz in section 121401E8. Hercynite (Hc) in grain next to sapphirine is largely altered to a transparent material (diaspore?). Plane light. (c) Photomicrograph of corundum in quartz in section 121401E4 – 2 (2 nd cut of slice yielding chopinite). Plane light

: Camparis analyses of chopinite (average from Table 6 ), Camparis analyses of biotite in grains 1 and 2 (Table 9 ), and analyses of synthetic (Mg, Fe) 3 (PO 4 ) 2 and biotite from London et al. (1999) .