Fig. 4: Magnified high-angle annular dark-field–scanning transmission electron microscopy image of the pseudo-magnetite in FIBii and corresponding elemental mapping.

The eleven arrows indicate metals for which the elemental ratio of iron and nickel is shown in SI Table S1. The original surface is at the left-hand side of the image. Note that a 30-nm-thick layer of carbon was deposited onto each face of the thin section. The widespread distribution of iron in the matrix surrounding the pseudo-magnetite exclusively is likely a result of its release from the framboid. The scale bar is 500 nm.