Extended Data Fig. 4: TEM data on coarse-grained sheet silicates from OREX-803095-100.
From: Mineralogical evidence for hydrothermal alteration of Bennu samples
(a) STEM-HAADF image. (b, c) BF-TEM images of the white box areas in panel (a). (d, e) SAED patterns from the areas in (b) and (c) outlined by white dashed circles. The SAED patterns show that some of the coarse-grained sheet silicates are poorly crystalline to amorphous in this region. Faint reflections can be observed with spacings that overlap serpentine and saponite. The spot mask is inserted in the SAED patterns to limit exposure by the direct beam. (f–k) STEM-EDS maps of (a) showing that the sheet silicates are mostly composed of Mg with minor Al and Fe. Sulfides occur throughout the section (cf., maps of Fe, S, and Ni with the HAADF image). The scale bars are 2.5 μm.
