Silicate melt removal and sulfide liquid retention in ultramafic rocks of the Duke Island Complex, Southeastern Alaska

Sulfide-silicate textures in magmatic Ni-Cu-PGE sulfide ore deposits: Disseminated and net-textured ores

“…There are no 3D images available for these samples, but it is likely that these sulfide inclusions and intergrowths actually represent interconnected networks that are intimately intergrown with the silicate phases. Stifter et al (2014) propose that these intriguing textures reflect downward percolation of sulfide melt and displacement of original silicate melt, along the lines of the mechanism proposed above for spinifex ore. We further suggest that the complex textures here may reflect an origin of the cumulus silicates as crescumulate dendritic (harrisitic) phases, which underwent partial textural equilibration before displacement of the interstitial silicate melt by percolating sulfide. It is noteworthy that the sulfide included in the symplectic intergrowths appears to be exclusively pyrrhotite, perhaps indicating that represents a true solid-solid symplectite produced by simultaneous growth of mss and pyroxene under water-rich conditions where both sulfide and silicate melts were between their liquidus and solidus over the same range of temperatures.…”

“…An unusual variant on net-textured ores is described from the Duke Island intrusion in the Alaskan Panhandle by Stifter et al (2014). These textures are developed within olivine-clinopyroxene-sulfide adcumulates where, instead of entirely occupying the interstitial space between the cumulus silicates, the sulfides also develop complex symplectic intergrowths with clinopyroxene and form subspherical inclusions (in two dimensions) in olivine.…”