Ferromanganese crusts draping rocks (and even old sponge stalks) at Fryer Guyot in the Mariana region.
Ferromanganese Crust
Image courtesy of the NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas. Download larger version (jpg, 1 MB).

Ferromanganese crusts draping rocks (and even old sponge stalks) at Fryer Guyot in the Mariana region.

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