Research directions
Phosphorus and Carbon burial during Cretaceous oceanic anoxic events, links with climatic changes
The main goal of this follow-on project is get a better understanding of mechanisms, which triggered Cretaceous oceanic anoxic events (OAE), more particularly, the paleoclimatic conditions which characterized the onset of major anoxic events and their evolution.
Recent works (Mort et al., 2007) show that the onset of the OAE 2 was triggered by a significant increased in phosphorus burial. The bottom waters became anoxic and switched from being a P sink to a P source, sustaining the productivity in a positive feedback loop.
The behaviour of Total Phosphorus (Ptot) and trace metals at larger scale, in different paleogeography and paleodepht is still poorly known.
We propose to investigate and compare two Cretaceous OAE events, at the Cenomanian-Turonian and Coniacian-Santonian transitions, which present respectively different level of anoxia: from intense and abrupt to moderate and gradual. Each OAE event will be investigate in different paleogeographic area at different paleodepths, using a multiproxy approach, which includes systematic analyses of phosphorus contents, stable-oxygen and carbon isotopes, trace elements, bulk and clay mineralogy, micropaleontology...
