Mid Cretaceous (Cenomanian - Turonian) black shales from ODP Leg 207 (western Central Atlantic) : Palaeoceangraphy deciphered by calcareous nannofossils

ODP Leg 207的5个地点（1257、1258、1259、1260、1261）恢复了中晚白垩世（晚阿尔比世-三东世）黑色页岩的良好记录。这些富toc的沉积物，在全球范围内以盖诺曼—吐鲁番界线带闻名，但在吐鲁番—三东统界线带却不太常见。后一时期的特点是半深海-远洋泥灰岩和灰岩。Turonian - Santonian黑色页岩可能反映了区域控制。钙质纳米化石是有用的生物地层学标志，可以在高分辨率尺度上进行生物分带。此外，它们是破译过去古生态代数据以重建营养通量的有力工具，从而使人们能够认识到生育力的变化。因此，我们计划对三个地点（1258、1260、1261）的晚Albian - turonian黑色页岩的钙质纳米化石进行分析，目的是：建立一个高分辨率的生物地层格架，了解赤道纳米化石的古生物地理及其气候含义，从钙质纳米化石生产力的角度来观察和解释黑色页岩的形成，破译全球和区域黑色页岩的沉积环境。

Five sites (1257,1258,1259,1260,1261) of ODP Leg 207 recovered a good record of Mid to Late Cretaceous (Late Albian - Santonian) Black shales. These TOC-rich sediments, globally well known from the Cenomanian/Turonian boundary interval, are less common in the Turonian - Santonian interval. This latter period is rather characterized by hemipelagic -pelagic marls and limestones. The Turonian - Santonian black shales presumably reflect a regional control. Calcareous nannofossils are useful biostratigraphic markers enabling a biozonation on a high resolution scale. They are furtheron a powerful tool for deciphering past palaeoecological proxy data for reconstructing nutrient fluxes, thus allowing the recognition of fertility changes. We therefore plan to analyse the calcareous nannofossils of the Late Albian - turonian black shales from three sites (1258,1260,1261) with the following objectives: to devolop a high resolution biostratigraphic framework, to understand the palaeobiogeography of equatorial nannofossils and their climatic implications, to view and interprete the black shale formation in the light of calcareous nannofossils productivity, to decipher the depositional enviroment of global and regional black shales.