Figure 2
Back scatter electron (BSE) images of the 1000 W specimen. The first two images show untreated JSC-1A. (a–c) show an overview of its fully-molten, partially-molten and sintered areas, respectively. (b,c) contain an abundance of mineral grains—olivine (Ol), plagioclase (Pl) and Fe-rich spinels (SPFe), embedded in a glassy matrix, and large vesicles. (d) is the detail of the box in (a) showing an oblate olivine grain (Ol) with a darker reaction rim caused by chemical re-equilibration with the melt. (e) is the detail of the box in (b) indicating SPFe formation from an olivine grain. (f) is the detail of the box in (c), showing the partial reaction of pyroxene (Px), olivine (Ol) and plagioclase (Pl) with the melt. (h) (the detail of the box in (g)) depicts the atypical dissolution shapes of olivine (Ol) with Dove- and H-shaped dendritic morphologies, which are highly euhedral with well-defined habit and growth pattern. Note that these patterns probably nucleated from the glass matrix. (i) shows iron oxide particles (likely to be titanomagnetite) arranged in orthogonal multiple cross-arm patterns growing euhedrally in a sintered area. Note that the contrast-brightness was adjusted to optimise the clarity of the image.
