A perfect, tablular slab of Manganese phosphorite (Mn-phos) was collected
along the flat top of Sponge Cliffs. Mn-phos is formed by the chemical
precipitation of phosphate directly from the seawater. When Mn-phos forms
sheet-like layers, we refer to it as "pavement."

Collected on JSLII Dive 3461, top pavement of Sponge Cliff, Blake Plateau (1700 ft).