Annotated record of the detailed examination of Mn deposits from DSDP Site 67, Leg 7 (Cores 67-1, 67A-2)@en

Site 67 is on the Hawaiian Arch, in the general region selected for one of the Mohole Project sites. Therefore, intensive geophysical surveys have been made in the area. The objectives were to penetrate the entire sedimentary sequence to basement in order to learn the petrology and ages of the sediments and of the seismic reflectors, and to obtain samples of the underlying basement rocks. Well consolidated and bedded volcanic sandstone and mudstone, and claystone were found to extend from the sea floor to a depth of 60 meters, where a layer of hard brown porcelanite stopped the bit. Displaced radiolarians in mud from a core at 60 meters indicate sediments of early Eocene or late Paleocene age are present somewhere above that depth.67号站位位于夏威夷海拱（Hawaiian Arch），处于莫霍计划（Mohole Project）预选站位的大致区域内。因此该区域已完成密集的地球物理勘测。本次钻探的核心目标为钻穿全部沉积序列直至基底，以探明沉积物与地震反射界面的岩石学特征及形成年代，并获取下伏基底岩石的样品。经勘探发现，从海底至60米深度区间内，分布有固结良好的层状火山砂岩、泥岩及黏土岩；而一层坚硬的棕色瓷质岩（porcelanite）于该深度处阻挡了钻头的钻进。取自60米深度岩心的泥浆中检出移位放射虫（radiolarians），表明该深度以上的地层中存在始新世早期或古新世晚期的沉积物。