Ferruginous conditions dominated later neoproterozoic deep-water chemistry.
Earth's surface chemical environment has evolved from an early anoxic condition to the oxic state we have today. Transitional between an earlier Proterozoic world with widespread deep-water anoxia and a Phanerozoic world with large oxygen-utilizing animals, the Neoproterozoic Era [1000 to 542 million years ago (Ma)] plays a key role in this history. The details of Neoproterozoic Earth surface oxygenation, however, remain unclear. We report that through much of the later Neoproterozoic (<742 +/- 6 Ma), anoxia remained widespread beneath the mixed layer of the oceans; deeper water masses were sometimes sulfidic but were mainly Fe2+-enriched. These ferruginous conditions marked a return to ocean chemistry not seen for more than one billion years of Earth history.
Canfield
Donald E
DE
Nordic Center for Earth Evolution and Institute of Biology, Campusvej 55, University of Southern Denmark, 5230 Odense, Denmark. dec@biology.sdu.dk
Poulton
Simon W
SW
Knoll
Andrew H
AH
Narbonne
Guy M
GM
Ross
Gerry
G
Goldberg
Tatiana
T
Strauss
Harald
H
D000818:Animals; D001272:Atmosphere; D019015:Geologic Sediments / Q000737:chemistry*; D046448:Ice Cover; D007501:Iron / Q000032:analysis*; D009792:Oceans and Seas; D010084:Oxidation-Reduction; D010100:Oxygen / Q000032:analysis*; D012623:Seawater / Q000737:chemistry*; D013431:Sulfates / Q000032:analysis; D013440:Sulfides / Q000032:analysis; D013995:Time
D013431:Sulfates; D013440:Sulfides; D007501:Iron; D010100:Oxygen