Annotated record of the detailed examination of Mn deposits from DSDP Leg 70 (Holes 506, 506B, 506C, 507C, 507D, 507F, 509, 509B)@en

The recovery of hydrothermal sediments at depth beneath the mounds of hydrothermal origin during a brief period of drilling on Deep Sea Drilling Project (DSDP) Leg 54 provided some evidence suggesting that hydrothermal material may be pervasive over a relatively large region inclusive of the mounds but also incorporating adjacent seafloor presently covered by pelagic sediments. As a result of the incomplete recovery of sediments at some sites and the poor recovery of basement rocks during Leg 54, it was suggested that a more carefully planned program be designed to drill a broader range of sites in the Galapagos mounds field. The major objectives of the first part of Leg 70 were to collect data and sediment representative of the hydrothermal mounds and ridges located about 20 km south of the Galapagos spreading axis.深海钻探计划（Deep Sea Drilling Project, DSDP）第54航次的短期钻探作业中，从热液成因丘体下方深部获取的热液沉积物岩心，为热液物质广泛分布于包含该类丘体在内的较大范围区域提供了实证——该区域同时涵盖了当前被远洋沉积物（pelagic sediments）覆盖的相邻海底。鉴于第54航次部分站位的沉积物回收率偏低，且基底岩（basement rocks）回收效果欠佳，学界提出应制定更为周密的钻探方案，在加拉帕戈斯热液丘场（Galapagos mounds field）布设覆盖范围更广的钻探站位。第70航次第一阶段任务的核心目标，是采集位于加拉帕戈斯扩张轴（Galapagos spreading axis）以南约20公里处的热液丘与热液脊的代表性数据及沉积物样品。