It has been suggested that the Cambrian ocean was oxygen deficient, but physical evidence for widespread anoxia has been lacking. Now, sulphur isotope data from Cambrian rocks at six different locations around the world is presented, with the finding of a positive sulphur isotope excursion in phase with a large excursion in the marine carbon isotope record, which is thought to be indicative of a global carbon cycle perturbation at the time. With the help of a box model, these isotope shifts support the idea of large-scale anoxic and sulphidic conditions in the later Cambrian ocean.
- Benjamin C. Gill
- Timothy W. Lyons
- Matthew R. Saltzman
