Cenozoic Deep Water History on Ceara Rise: An Integrated Geophysical and Sedimentological Survey

在过去的几年里，海洋钻探项目采用了一种采样策略，即在地震带上钻取等深样条，以重建碳酸盐岩生产和溶解的新生代历史，以及深水化学和循环。这种策略是从类似的研究晚第四纪海洋学历史的浅层取心项目演变而来的。深度样带最浅处的碳酸盐聚集近似于上覆水域的碳酸盐生产力。如果这些地点靠得很近，而且只在深度上有所不同，那么积累速率将记录碳酸盐的溶解，而碳酸盐的溶解将受到底部水化学变化的控制。本项目的目的是获取西赤道大西洋西阿拉海隆的地震数据和岩心样本。西阿隆起被一层厚厚的新生代沉积物覆盖，应该是进行深度样带研究的理想地点。此外，所获得的数据将为该地区提出的详细ODP钻井计划奠定基础。

During the last few years, the Ocean Drilling Program has employed a sampling strategy in which bathymetric transects are drilled on aseismic ridges in order to reconstruct the Cenozoic history of carbonate production and dissolution, and deep water chemistry and circulation. This strategy has evolved from similar shallow coring programs examining late Quaternary oceanographic history. Carbonate accumulation in the shallowest sites of the depth transect approximates carbonate productivity in the overlying waters. If the sites are close together and only vary in depth, the accumulation rates will record carbonate dissolution which will be controlled by changes in bottom water chemistry. The objective of the present project is to acquire seismic data and core samples from the Ceara Rise in the western equatorial Atlantic. The Ceara Rise is capped by a thick section of Cenozoic sediments and should be an ideal site for a depth transect study. Additionally, the data to be acquired will form the basis for a detailed ODP drilling program which has been proposed for this area.