DEVELOPMENT OF COMPOSITE DEPTH SECTIONS FOR SITES 844 THROUGH 854 1
DEVELOPMENT OF COMPOSITE DEPTH SECTIONS FOR SITES 844 THROUGH 854 1
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为 844 至 854 号地点开发复合深度剖面 1
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
N. Pisias
中科院分区：
文献类型：
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作者：
T. Hagelberg;N. Shackleton;N. Pisias
第138航次的一个主要目标是获取赤道太平洋新近纪气候变化的高分辨率记录。与这一目标相一致的是恢复连续记录的重要性。如果操作得当，在给定的位置钻多个相邻的孔有助于确保恢复连续的记录。在过去，只有在钻井完成后才能确认连续段的恢复，即使在那时也很困难。在第138航次期间，在每个地点使用连续测量的岩性参数进行钻探期间，对多个钻孔的记录进行了处理和检查。这一过程有助于确保在每个地点恢复几乎完整的地层序列，并允许真实的改变钻井计划。虽然这里讨论的是对第138航次数据的最终分析，但我们发现，取芯的地层剖面必须首先用有用的深度标度表示。在几次DSDP和ODP巡航期间记录后（例如，第85、86、94、108、111、115、117和121段），科学家们现在知道，在一个给定孔中连续的APC岩心之间，部分沉积序列往往无法恢复。为了在138航次现场拼凑出一个连续的沉积剖面，我们制作了一个复合深度剖面。该深度剖面是通过将给定位置处相邻钻孔的岩心拼接在一起而形成的。复合剖面的目的是通过将每个钻孔与一个共同的深度标度相比较，描述特定地点的整个沉积序列。通过从每个钻孔中识别沉积序列的缺失部分，并从相邻的钻孔中进行修补，可以对连续的记录进行采样。一个完整的复合部分的建设也提供了一个初始的地层框架的网站，这使我们能够参考磁性地层和生物地层事件在不同的孔观察到一个共同的深度尺度。
A primary objective of Leg 138 was the acquisition of high-resolution records of Neogene climatic change in the equatorial Pacific Ocean. Coincident with this objective was the importance of recovery of a continuous record. If properly done, drilling multiple adjacent holes at a given site helps assure recovery of a continuous record. In the past, confirmation of recovery of a continuous section only occurred after drilling had been completed and even then was difficult. During Leg 138, records from multiple holes were processed and examined during drilling at each site using continuously measured lithologic parameters. This process helped to ensure the recovery of a nearly complete stratigraphic sequence at each site and allowed for changes in drilling plans in real time. Although much of the final analysis of Leg 138 data is here discussed in terms of time, we found it essential that the stratigraphic sections cored were first expressed with a useful depth scale. After being documented during several DSDP and ODP cruises (e.g., Legs 85, 86, 94, 108, 111, 115, 117, and 121), scientists now know that between successive APC cores in a given hole, part of the sedimentary sequence is often not recovered. To piece together a continuous sedimentary section at the Leg 138 sites, we developed a composite depth section. This depth section was formed by splicing together cores from adjacent holes at a given site. The purpose of the composite section was to describe the entire sedimentary sequence at a given site by referencing each hole to a common depth scale. By identifying the missing parts of the sedimentary sequence from each hole and by patching in from adjacent holes, a continuous record could be sampled. The construction of a complete composite section also provided an initial stratigraphic framework for the site, which allowed us to reference magnetostratigraphic and biostratigraphic events observed in different holes to a common depth scale.