This project will try to answer two crucial questions concerning the origin of the Oceanic anoxic events (OAE)s: What triggered the Phosphorus Accumulation at the onset of the ?13C shift of OAE2 (Cenomanian-Turonian) and: is P MARs showing the same distribution pattern in other OAEs (e.g. during the Coniacian-Santonien OAE events). In recent years, a renewed effort to understand greenhouse conditions, global biogeochemical cycles, and feedback mechanisms, has focused on the Cretaceous anoxic events as a natural laboratory of the past and analog for the future greenhouse warming. It is hoped that understanding the greenhouse world climatic evolution which led to such events, and implies increase in atmospheric CO2, changes in productivity, and biotic survival and extinction rates, will help predict negative consequences of future greenhouse warming due to anthropogenic emissions of CO2. Despite the common knowledge that these sequences may hold critical information regarding the origin and cause of the greenhouse warming, anoxic event, and biotic stress and extinctions, and despite the large amount of isotopic proxy data accumulated to date, a convincing model of climatic evolution for the OAEs has yet to be developed. A multidisciplinary approach and using both latitudinal and depth transects may just yield the necessary data to reconstruct the OAEs paleoclimatic evolution, greenhouse warming and high organic matter accumulation. By comparing with the OAE2, we especially to explain better the last OAE (3) which ended the hot Cretaceous Greenhouse period. Our project is broadly based both geographically and scientifically focusing on bulk and clay mineralogy, phosphorus coupled to organic carbon accumulation and other paleoproductivity geochemical indicators, quantitative micropaleontology in order to assess the change in weathering processes due to greenhouse conditions and its influence on paleoproductivity and/or organic carbon preservation. Moreover, our project will address the critical questions of the anoxic events, greenhouse warming and biotic response on a broad latitudinal basis form low to high latitudes, eastern to western Tethys and depositional environments ranging from shallow shelf to basins, continental margins to slope environment. This approach is expected to yield limiting conditions for the production of organic-carbon-rich shales and adverse biotic conditions in both vertical (depth) and latitudinal dimensions. To our knowledge no comprehensive data of this nature exist to date.