Towards an Astronomically Calibrated Late Cretaceous to Early Paleocene Time Scale

赫伯特9526639 最近的40 Ar/39 Ar测年证实了轨道调谐方法对地球磁极时标（GPTS）上新世和更新世部分的改变。 由于轨道周期在地质学上以较短的增量来标记时间，因此它们可以用来非常精确地测量事件之间的时间，例如磁性逆转或生物地层基准。 我们概述了一个工作计划，以改善和完善的白垩纪和古新世早期的部分GPTS，这是一个间隔，这是受到错误的扩展速率变化在南大西洋海底模板通过研究一些DSDP/ODP钻井现场晚白垩世到古新世早期的年龄，显示岁差（20千年重复时间）强迫碳酸盐循环。 高分辨率的古地磁采样将与收集数字时间序列（彩色反射光谱法）相结合，以产生一个复合天文年表的磁时C33 R到C27 N（83 Ma至62 Ma）。 由此产生的GPTS的改进将用于地球动力学家，生物地层学家和古海洋学家。

Herbert 9526639 Recent 40Ar/39Ar dating has validated changes made to the Pliocene and Pleistocene portions of the Geomagnetic Polarity Time Scale (GPTS) by orbital tuning methods. Because orbital cycles mark off time in geologically short increments, they may be used to measure elapsed time between events such as magnetic reversals or biostratigraphic datums very precisely. We outline a work plan to improve and refine the Cretaceous and early Paleocene portion of the GPTS, an interval which is subject to errors from spreading rate changes in the South Atlantic sea-floor template by studying a number of DSDP/ODP drill sites of late Cretaceous to early Paleocene age that display precessionally (20 kyr repeat time) forced carbonate cycles. High resolution paleomagnetic sampling will be combined with gathering digital time series (color reflectance spectrometry) to produce a composite astronomical chronology for magnetochrons C33R through C27N (83 Ma to 62 Ma). The resulting improvement in the GPTS will be of use to geodynamicsts, biostratigraphers, and paleoceanographers.