Clark Johnson on the Banded Iron Formations

Glossary

Alvin - a crewed deep-ocean research submersible operated by the Woods Hole Oceanographic Institution.

diagenetic pathways - the physical and chemical processes that affect sedimentary materials after deposition and before metamorphism or weathering.

ferric and ferrous iron – in ferric iron, the iron atom has lost three electrons to form a Fe+3 ion; in ferrous iron, the iron atom has lost two electrons to form a Fe+2 ion.  Also designated FeII and FeIII.

varves - layers of lake or marine sediments that represent an annual cycle of sedimentation.

reductive pathways – geochemical reactions that involve the reduction of iron from a more oxidized state to a less oxidized state, e.g., from Fe+3 to Fe+2.