Probing the Deep Sea Sediment Record: Open Ocean History and Biotic Evolution

The astonishing developments in understanding the Earth as an evolving integrated system has resulted, during the last four decades, from a complex interplay between new technologies including ocean drilling, the acceptance of plate tectonics and a succession of critical paradigm shifts involving past Earth system processes. Paleontological investigations of the extraordinarily well-preserved deep-sea microfossil record have been central in these advances including the development of paleoceanography; many pioneer paleoceanographers were micropaleontologists. Much of the early understanding of the history of the Cenozoic Ocean was based on paleontological proxies, and marine microfossils remain the preferred material for geochemical studies because of sufficient paleocological context.

The development of marine microfossil biostratigraphy represented an early, crucial step for paleoceanography because of the need for global stratigraphic correlation. Integrative stratigraphy resulted that related multiple microfossil sequences, magnetostratigraphy and chemostratigaphy for the last ~100 mys, as well as providing a reliable, high-resolution time scale.

The deep-sea paleontological enterprise has led to a host of major breakthroughs towards a broad understanding of the Earth as an evolving system. These include: a dramatically improved understanding of the biotic and paleoenvironmental basis for the divisions of the Cenozoic and the extension of this knowledge to the older record; the discovery that the ocean at all depths is not simple and unchanging but is a critical and dynamically changing part of the global system; improved understanding of the nature of the planktonic realm, its evolution, productivity, paleoecology and how this realm has influenced the ocean sediment record; quantitative use of planktonic microfossils to estimate past temperatures and other conditions of the surface ocean; and contributions towards understanding of evolutionary processes and theory.