Annotated record of the detailed examination of Mn deposits from DSDP Leg 39 (Holes 354, 355, 356, 358, 359)@en

Unlike most previous Deep Sea Drilling Project cruises, Leg 39 was not scientifically planned as a \"theme\" cruise, on which a number of sites are drilled to address a single scientific problem area, namely, to improve our knowledge of paleocirculation changes and the overall geologic history of the South Atlantic Ocean. This would be done along more specific objectives: 1) collect a biostratigraphic section on the Ceará Rise (Site 354), determine the nature and age of a prominent reflector there, and determine the nature and age of basement; 2) date basement between magnetic anomalies 32 and 33 in the Argentine Basin (Site 358), and 33 and 34 in the Brazil Basin (Site 355); obtain as complete sedimentary sections as time would permit at the Ceará Rise, Brazil Basin, the Argentine Basin and Sào Paulo Plateau (Site 356).与此前绝大多数深海钻探计划（Deep Sea Drilling Project）航次不同，第39航次并未按照“主题航次”的模式开展科学规划——主题航次会通过钻探多个站位，聚焦单一科学问题领域，即加深我们对古环流变化以及南大西洋整体地质历史的认知。本次航次的科学目标更为具体，分为以下三项：1）在塞阿拉海隆（354号站位）获取生物地层剖面，明确该处一处显著反射层的性质与形成年代，并测定基底的性质与年代；2）测定阿根廷盆地（358号站位）磁异常32与33之间的基底年代，以及巴西盆地（355号站位）磁异常33与34之间的基底年代；3）在时间允许的前提下，尽可能完整获取塞阿拉海隆、巴西盆地、阿根廷盆地以及圣保罗高原（356号站位）的沉积剖面。