Cycles of nutrient trace elements in the Phanerozoic Ocean and relationship to atmosphere-ocean oxygenation

Redox sensitive and nutrient trace element (TE) concentrations in the palaeo-ocean have commonly been interpreted to rise abruptly toward the end of the Neoproterozoic, and remain relatively constant through the Phanerozoic. This pattern has been considered to relate to a second stage of Earth oxygenation, resulting in, or a consequence of, the Cambrian explosion of life. Here we present a comprehensive dataset on the trace element content of marine sedimentary pyrite that defines several TE concentration cycles, on 70 to 120 million year wavelengths, with amplitude variations of several orders of magnitude. The cycles, which start in the Neoproterozoic and are best developed through the Paleozoic, have a similar pattern to the ocean ⁸⁷Sr/⁸⁶Sr record, suggesting that continental erosion and nutrient supply maybe a first order driver of the TE cycles. Molybdenum, thallium, selenium, cadmium, antimony and ⁸⁷Sr/⁸⁶Sr pattern. The contrasting pattern of cobalt, which is demonstrated on all scales from a few million to a billion years is most probably due to its decrease in solubility under conditions of increasing oxidation. This opposite behavior to the other TE, implicates oxygenation as a second order driver of the redox sensitive TE cycles, and enables the tentative construction of an oxygenation curve for the Phanerozoic.