Local rapid transgression and the availability of organic material in marine sediments appear to be important factors to produce subsesequent mineralization. By focusing on syngenetic deposits, we avoid the complication of interpreting the time and manner of the introduction of the ores or ore-bearing fluids after diagenesis. Accordingly, dating of both the sediment and the postulated influencing global event is not a problem. He describes the geologic setting as an organic-rich marine shale overlying continental red beds. Basically their concept is that the amount of organic matter preserved in the geologic record can be used to predict atmospheric compositions with time.
Carbon is stored and preserved during intervals of low amounts of atmospheric oxygen.
Budyko et al . Thus during deposition of marine sediments, the redox conditions in the overlying water is strongly influenced by atmospheric oxygen concentrations. True anoxia in the water column is only seen in barred basins like the Black Sea and the Cariacao Trench or the Arabian Sea where there is no or only limited connection to deep ventilated waters from high latitudes. However, later deposits in the Jurassic and younger do not seem to correlate with low atmospheric oxygen, and in fact are coincident with atmospheric values greater than modern. Local sea level fluctuations certainly occur within the Wilson cycle as a result of rifting and accretion of various terranes.