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

ODP航次207的5个地点（1257、1258、1259、1260、1261）恢复了中晚白垩世（晚Albian - Santonian）黑色页岩的良好记录。这些富含TOC的沉积物在Cenomanian/Turonian边界层段中是全球知名的，但在Turonian - Santonian层段中不太常见。后一时期以半远洋-远洋泥灰岩和石灰岩为特征。图伦-桑顿黑色页岩可能反映了区域控制。钙质超微化石是一种有用的生物地层标志物，可以在高分辨率尺度上进行生物分带。它们进一步成为破译过去古生态替代数据以重建营养通量的强大工具，从而能够识别生育力变化。因此，我们计划分析来自三个地点的晚Albian - turonian黑色页岩的钙质超微化石（1258，1260，1261），目标如下：建立高分辨率的生物地层格架，了解赤道超微化石的古生物地理及其气候意义，根据钙质超微化石的产率来观察和解释黑色页岩地层，解读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.