SEM images of Fe–Si–Mn oxyhydroxides from Franklin Sea-mount. (a) Typical filamentous texture, sample M2170-8 (106905). (b) Apparently branching filaments thickened by silica carapaces (see arrow), sample M2202-6 (106925), photograph courtesy of Katsumi Marumo, Geological Survey of Japan, Japan, (c) Bunched filament made of parallel strands surrounded by amorphous iron agglomerates (see arrow), sample M2202-2a-1 (106920). (d) Short braided stalk in center (see arrow) surrounded by amorphous iron oxyhydroxides, M2202-2a-1 (106920). (e) Formless agglomerates of amorphous iron oxyhydroxide, sample M2202-2a-1 (106920). (f) and (g) Filaments (see arrows) attached or growing outwards from agglomerates of amorphous iron oxyhydroxide, M2192 loc. 1 (106848). Spot energy dispersive spectroscopy analyses show no significant compositional difference between the filamentous and formless textures, (h) Degraded filaments, M2170-2B (106899). Note the lack of degradation in those filaments adjacent to the formless textures in (c), (d), (f) and (g); these textures are very different from (h).