Synthesis of magnetostratigraphy of the Cretaceous System in the northwest Pacific: Results from the Nemuro Group and the lower Yezo Group

西北太平洋白垩系磁性地层综合：根室群和下虾夷群的结果

基本信息

批准号：
14540439
负责人：
KODAMA Kazuto
金额：
$ 1.98万
依托单位：
Kochi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540439/
关键词：
Cretaceous System magnetostratigraphy Nemuro Group Yezo Group Hokkaido Sakhalin 羽幌古丹別

项目摘要

This study provides a new magnetostratigraphic data from the lower Yezo Group and the Nemuro Group in Hokkaido, Japan. Compilation of this data set and those from elsewhere as Kyushu, Shikoku and Sakhalin of Russian Far East leads to a comprehensive, intra-regional correlation of the Upper Cretaceous strata in the Northwest Pacific, which can be calibrated to the geomagnetic polarity time scale in the late Cretaceous. The combined magnetostratigraphic and biostratigraphic correlation has assigned these zones to the Late Cretaceous geomagnetic polarity chrons including C31r through C33r and the Cretaceous long normal interval. Corresponding geomagnetic reversals have been documented from the Upper Cretaceous successions of the Western Interior of North America, in combination with high-resolution ammonite biostratigraphy and radiometric age dates. Biostratigraphy of the Great Valley Sequence in California is also well-defined, but there is only one reversed interval that can be correlated with polarity chron C33r. The most complete record of polarity reversals in South Sakhalin would provide an integrated reference scheme which can be of significant use not only to correlate dissimilar faunal assemblages of disparate regions in the North Pacific, but also to contribute to a global definition of Upper Cretaceous stage boundaries.

这项研究提供了来自日本北海道的下Yezo组和Nemuro Group的新磁性数据。该数据集以及来自其他地方的数据集的汇编，俄罗斯远东地区的九州，Shikoku和Sakhalin会导致西北太平洋上白垩统地层的全面，区域内相关性，可以校准在后期白垩纪的地质极性时间。联合磁层学和生物地层的相关性已将这些区域分配给了晚白垩纪的地磁极性雄性，包括C31R通过C33R和白垩纪长的正常间隔。从北美西部内部的白垩纪上部延伸中，已经记录了相应的地磁逆转，并结合了高分辨率的氨矿生物地层学和放射年龄的日期。加利福尼亚大山谷序列的生物地层学也是明确的，但是只有一个反向间隔可以与极性Chron C33R相关。南萨哈林南部极性逆转的最完整记录将提供一个综合的参考方案，该方案不仅可以与北太平洋不同区域的不同动物组合相关联，而且有助于全球上白垩纪阶段边界的定义。