Summary

There is an unsullied lineage in biostratigraphy from 19C zones to the ISSC Guide, then to the integrated geo-magneto-bio-chrono-logical scale based on the ordination and first-order correlation of irreversible events. However, a shift in worldview away from Lyellian gradualism has encouraged systemic stratigraphy, a Quaternary-type systems approach to the use of regional signals of global environmental changes at third-order and higher frequencies. Thus the mainstream of biostratigraphy is now conjoined with another: ecostratigraphy and sequence biostratigraphy, where the reversible events of biofacies shifts and chemostratigraphy together with depositional surfaces can be constrained by classical zones or datums. Sequence biostratigraphy has three aspects: basin analysis, integration with the main scale, and as a template for Cenozoic palaeobiology. A plausible global model of third-order marginal sequences and δ18O-based glaciations can be tested to some degree (and successfully) by neritic biofacies studies.

Systemic stratigraphy

Converting microplanktonic stratigraphic ranges into evolutionary ranges, and tying those fundamental bioevents to physical events such as the geomagnetic chronology, was central to Chapter 3. We are going beyond that here. Correlation is opportunistic in the broadest possible chronological sense in that any and all signals in the exogenic system can be invoked. The global ocean is controlled ‘endogenically’ by crustal processes which control the volume of ocean basins and thereby sealevel, or the spillage of water across the continental margins, and by the intensity of cycling and exchange into the crust through the ridge systems.