Composite depth scales, ash layer correlations and splice tie points of ODP Site 186-1151@en

We present composite depth scales for the multiply cored intervals from Sites 1150 and 1151. These new depth scales place coeval strata recovered in cores from different holes at a single site into a common stratigraphic framework. At Site 1150, double coring between Holes 1150A and 1150B occurred over only a short interval between ~703 and 713 meters below seafloor (mbsf), but this is sufficient to tie the upper portion of the stratigraphic section cored in Hole 1150A to the lower portion cored in Hole 1150B. The upper ~100 m of the sedimentary section at Site 1151 was double cored with the advanced piston corer and partially cored with the rotary core barrel, resulting in the complete recovery of this interval. The composite depth scales were constructed using Splicer software to vertically adjust the relative depths of various cores from one hole to the depths from another hole so as to align distinct physical properties measured on cores. The magnetic susceptibility data was the physical property most easily correlated between holes, and therefore primarily used to create a composite depth scale and spliced stratigraphic section. The spliced section is a continuous stratigraphic section constructed from representative cored intervals from the holes at a site. Both the splice and the composite depth scale can be applied to other data sets from Site 1151 to provide a stratigraphically continuous and laterally consistent basis for interpreting lithologic features or data sets. The resulting composite scale showed a 30% improvement in correlation of the magnetic susceptibility data relative to the original mbsf depth scale, and comparable improvement when applied to the other data sets.本研究为1150站位与1151站位的多取心层段构建了复合深度标尺。该套新型深度标尺可将单一站位不同钻孔所取岩心中的同年代地层纳入统一的地层格架。在1150站位，1150A与1150B钻孔仅在海底以下约703至713米（meters below seafloor, mbsf）的短层段开展了双取心作业，但该层段已足够将1150A钻孔取心获得的地层上段与1150B钻孔取心获得的地层下段进行关联。1151站位沉积剖面的上段约100米采用高级活塞取心器（advanced piston corer, APC）开展双取心，并辅以旋转岩心筒（rotary core barrel, RCB）进行部分取心，最终实现了该层段的完整取心。本研究采用Splicer软件构建复合深度标尺，通过垂向调整单一钻孔内各岩心的相对深度，使其匹配另一钻孔的深度基准，从而对齐岩心实测的各项物理特性数据。磁化率数据是不同钻孔间最易关联的物理特性参数，因此被主要用于构建复合深度标尺与拼接地层剖面。拼接剖面是由站位各钻孔的代表性取心层段整合而成的连续地层剖面。该拼接剖面与复合深度标尺均可应用于1151站位的其他数据集，为岩性特征或各类数据集的解译提供地层连续、横向一致的基准框架。最终得到的复合深度标尺相较原始海底以下米数深度标尺，使磁化率数据的关联精度提升了30%，且在应用于其他数据集时也取得了相当的精度提升效果。