Annotated record of the detailed examination of Mn deposits from DSDP Site 66, Leg 7 (Cores 66-4, 66-6, 66-9, 66-10, 66A-3, 66A-5)

One of the principal objectives in the Central Pacific Basin was to elucidate the Paleobathymetric history of the region, which is located amidst groups of atolls and guyots that have subsided as much as 2 kilometers since mid-Cretaceous times. After failure to penetrate the entire sedimentary section and to sample basement at Site 65, on the west side of the Central Basin another site in the Basin where basement rocks might be sampled was searched. Likely places were known from unpublished reflection profiles on the east side of the Basin near the Line Islands by the Hawaii Institute of Geophysics. Finally it was decided to drill a transparent section once again in this area acoiding turbidites formations.

本研究在中太平洋海盆的核心目标之一，是阐明该区域的古水深演化历史（Paleobathymetric history）——该区域坐落于成群环礁（atolls）与平顶海山（guyots）之间，这些环礁和平顶海山自白垩纪中期以来已沉降达2公里之多。此前在中央海盆西侧的65号钻探站位未能穿透完整沉积剖面（sedimentary section）并获取基底岩样（basement rocks），因此研究团队转而在海盆内搜寻可采集基底岩样的其他站位。夏威夷地球物理研究所（Hawaii Institute of Geophysics）此前在海盆东侧靠近莱恩群岛（Line Islands）区域获取的未公开反射地震剖面（reflection profiles），已标注出潜在的合适站位。最终，研究团队决定在该区域再次开展钻探，以获取匹配浊积岩地层（turbidite formations）的完整透明剖面。