1. ONLINE RESOURCE FIGURES Nickel-rich metasomatism of the lithospheric mantle by pre-kimberlitic alkali-S-Cl-rich C-O-H fluids Andrea Giuliani*, Vadim S. Kamenetsky, Mark A. Kendrick, David Phillips and Karsten Goemann submitted to: Contribution to Mineralogy and Petrology * corresponding author School of Earth Sciences, The University of Melbourne email: a.giuliani@student.unimelb.edu.au 1 cm Figure 1EA Figure 1EA. Photograph showing an off-cut of sample XM1/422

2. d Spl Ni Ol Figure 2EA. SEM back-scattered electron (BSE) photos of minerals in xenolith XM1/422. a-b) Different types of spinel (Spl) + diopside (Dps) + orthopyroxene (Opx) symplectites after garnet or Al-Cr-Ca-rich orthopyroxene; c) Ni mineralisation with heazlewoodite (Hz) in the core, surrounded by granoblastic domains of dominant Ni-Fe-rich olivine (Ni-Ol); d-e) blebs of native nickel interstitial to coarse-grained porphyroblastic olivine (Ol); in e) native nickel associated with fine-grained Ni-Fe-rich olivine. Ol porphyroblastic olivine; Srp serpentine a Spl Dps c Spl Opx e Ol Hz Ni Ni-Ol Hz c Ni-Ol Srp Figure 2EA

3. e Ni Ol Hz Mgt a Phl Spl Srp b Ol Dps NiSpl Srp d Ni Hz Srp Spl Figure 3 EA Figure 3EA. FESEM BSE (a-d,f) and secondary electron (SE; f) images of minerals in spinel + pyroxenes symplectites and Ni-rich assemblages of xenolith XM1/422. a) 700× view of altered margin of spinel + pyroxenes symplectite with formation of Ni-poor phlogopite (Phl) and re-crystallisation of spinel (Spl) to grains with abundant inclusions and variable BSE response (altered Ni-poor spinel); b) large, composite Ni-rich assemblage; c) discontinuous heazlewoodite vein (white box) connecting different Ni-rich assemblages; d) grain of native nickel (Ni) marginally replaced by heazlewoodite (Hz); e) magnetite (Mgt) + heazlewoodite (Hz) intergrowths replacing the margins of native Ni; f) 4000× view of native nickel included in porphyroblastic olivine (Ol; see Fig.3f). Dps diopside; Srp serpentine c Ni Dps Ol Hz f Ol core Ol rim Ni Srp Hz

4. Figure 3EA, continue h Ni-Ol Cpx1 Cpx2 i Ni-Ol Hz j Srp Ni-Ol Hz Ni-Fe-Ti Spl Figure 3EA, continue. FESEM BSE (g,h,j) and SE (i) images of minerals in Ni-rich assemblages of xenolith XM1/422. g) Granoblastic domain of abundant Ni-Fe-rich olivine (Ni- Ol) in contact with a grain of native nickel; h) compositional variability of Ni-Fe-rich clinopyroxene (Cpx1 and Cpx2) included in Ni-Fe-rich olivine; i) heazlewoodite (Hz) inclusion in Ni-Fe-rich olivine; j) inclusions of heazlewoodite, Ni-Fe-Ti-rich spinel (Ni-Fe-Ti Spl), apatite and carbonates (not shown) in Ni-Fe-rich olivine. Ol porphyroblastic olivine g Ni-Ol Ni Ni-Spl Ol

5. Figure 4EA Figure 4EA. Image and EDS spectra of inclusions in altered Ni-poor spinel associated with Ni- poor phlogopite (phl) from the margin of an altered spinel + pyroxenes symplectite (on the vertical axis of EDS spectra is the relative peak intensity of each element). The inclusions host several alkali and volatile-rich minerals including phlogopite, dolomite, apatite, bradleyite, alkali- carbonates (e.g. zemkorite), chlorides (e.g. halite) and Ni-Fe sulphide. Note the variable BSE response of spinel due to variations in Cr, Al, Fe, Mg and Ti contents. phlogopite dolomite ± bradleyite phlogopite ± halite zemkorite Ni-Fe sulphide bradleyite + apatite spinel phl

6. Hz rel. peak intensity Ni-Co-rich pentlandite Cu sulphide native copper Figure 5EA Figure 5EA. Image and EDS spectra of inclusions of Ni-Co-rich pentlandite, native copper and Cu sulphide in heazlewoodite (Hz).

7. Figure 6EA calciteapatite alkali-carbonate heazlewoodite Ni-olivine (host) rel. peak intensity Figure 6EA. Image and EDS spectra of polymineralic inclusion in Ni-Fe-rich olivine. The inclusion host grains of heazlewoodite, apatite, calcite and alkali-carbonate.

8. Figure 7EA spinel (host) glass inclusion devitrified glass inclusion rel. peak intensity Figure 7EA. Image and EDS spectra of Si-P-Ca-K-Na-Cl glass inclusions in Ni-Fe-rich relict spinel. Note that the glass inclusions display negative shape of the spinel host.

9. Figure 8EA 6 4 Ni Hz b NiOl core Ni Ol core Figure 8EA. Positions of chemical profiles in porphyroblastic olivines adjacent to heazlewoodite (a) and native nickel (b). 2 7 Hz a Ol core HzHz

10. SNi SiMgFe CaCP Figure 9EA. x-ray elemental map of large heazlewoodite (Hz) grain and Ni-Fe olivine (Ni- Ol)-rich granoblastic domain in a Ni-rich assemblage. Note the occurrence of Ca-rich carbonate and apatite in the Ni-rich assemblage. Ol porphyroblastic olivine; Dps diopside Figure 9EA 100 μm Hz Ol Dps Ni-Ol

11. Ni S FeSiMg PCaCr Figure 10EA Figure 10EA. x-ray elemental map of a Ni-rich assemblage that includes a large grain of native nickel (Ni). Nickel-Fe-rich olivine (Ni-Ol) adjacent to native nickel is preferentially enriched in Fe compared to Ni. Note the abundance of relict spinel (Spl), and the occurrence of apatite. Ol porphyroblastic olivine 100 μm Ni Ol Ni-Ol Spl