Spectral Stratigraphy of DSDP and ODP Cores from the Equatorial Pacific

最广泛使用的方法高分辨率海洋 地层学依赖于delta-018变化的记录， 古生物学或古地磁学。 不幸的是，这些技术 仅限于富含碳酸盐或二氧化硅的沉积物， 或来自磁性定向的核心。 博士 赫伯特将开发使用GRAPE（伽马射线）的技术 衰减孔隙度评价器）体积密度测量， 确定5个DSDP和ODP核心的轨道频率， 赤道东太平洋 这些“米兰科维奇”信号是 在2%的精度内已知通过新第三纪， 作者打算“调整”沉积速率，以适应这些 频率. 初步工作已经肖恩说，一个“移动窗口” 该方案将产生5%的精度和100 Kyr的分辨率， 沉积速率回到17 MY。 因为这是一个发展 实验中，他提出了几个验证检查， 现有的生物地层学和古地磁校准，以及 作为站点间一致性检查。 如果发现有效， 技术不仅提供了大大改进年表， 这些和其他核心，但也将：1）使同样可能 改进了CaCO 3、Corg、SiO2 （2）第一次有机会发现 古海洋周期大于500 Kyrs; 3） 更好地理解轨道的均值和方差 回到17我的力量。

The most widely used methods of high-resolution marine stratigraphy rely on the record of changes in delta-018, paleontology or paleomagnetics. Unfortunately, these techniques are limited to sediments either rich in carbonate- or silica- bearing fossils, or from magnetically oriented cores. Dr. Herbert will develop techniques for using GRAPE (Gamma Ray Attenuation Porosity Evaluator) bulk density measurements to identify orbital frequencies in 5 DSDP and ODP cores from the equatorial eastern Pacific. These "Milankovitch" signals are known within 2% precision back through the Neogene, and the author intends to "tune" the sedimentation rates to fit these frequencies. Preliminary work has shaon that a "moving window" scheme will result in 5% precision and 100 Kyr resolution of sedimentation rates back to 17 MY. As this is a developmental experiment, he proposes several validation checks against existing biostratigraphy and paleomagnetic calibrations, as well as inter-site consistency checks. If found to be valid, this technique will not only provide much improved chronologies at these and other cores, but will also: 1) make possible equally improved mass accumulation rate estimates for CaCO3, Corg, SiO2, and aeolian dust; 2) provide the first chance of finding paleoceanographic periodicities longer than 500 Kyrs; and 3) lead to better understanding of the mean and variance of orbital forcings back to 17 MY.