Establishment of utility ranking for fossil datum planes in Upper Cretaceous sequences based on carbon isotope stratigraphy.

基于碳同位素地层学的上白垩统化石基准面效用排序的建立

基本信息

批准号：
13640469
负责人：
HASEGAWA Takashi
金额：
$ 2.18万
依托单位：
Kanazawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

(1)About two kilometers of detailed plan map(1/1000) along Horotate River in Kotanbetsu, Tomamae Town, Hokkaido, Japan was drawn based on measurement and careful investigation of macro fossil occurrences. Plan maps in 1/5000 scale were also made in the Oyubari, Hobetsu and Haboro areas. Mudstone samples were collected during the survey and the localities are indicated within these plan maps.(2)Along Horotate River, macrofossil did not show abundant occurrences, however, continuous occurrence of regionally important age indicative species, namely Inoceramus hobetsensis, was identified. It enabled us to delimit the stratigraphic distribution of this species in detail.(3)Carbon isotope analysis on majority of samples from Horotate River sequence have been suspended because of machine troubles at an institute where we have expected to analyze them. Samples from Oyubari and Hobetsu areas and a part of samples from Horotate River sequence were analyzed at Indiana University, U.S.A.Each carbon isotope profile for each area showed internationally recognizable pattern that enables us to calibrate biohorizons of macrofossil within the framework of international correlation.(4)Planktonic foraminifers from Hobetsu area include variety of age indicative species. Among them, continuous occurrence of Helvetoglobotruncana helvetica addresses stratigraphic range of internationally significant foraminiferal zone. Four other cosmopolitan species also support stratigraphic position of upper limit of H.helvetica Zone in this area.(5)Continuous effort for establishment of detailed chronostratigraphy for the Cretaceous in Hokkaido will be carried out after this project. Such data collection will open the way for utilizing the Yezo Group as an international chronological standard succession.

（1）根据测量和仔细研究宏化石发生的情况，绘制了日本北北鸟镇的Horotate River的详细计划图（1/1000）。在Oyubari，Hobetsu和Haboro地区还制作了1/5000比例的计划地图。在调查过程中收集了泥岩样品，并在这些计划图中指示了地方。（2）沿Horotate River，大化石并未显示出丰富的发生，但是，鉴定出了持续的区域重要年龄指示性物种，即hobetsensis，即确定。它使我们能够详细地界定该物种的地层分布。（3）由于机器序列的大多数样品的碳同位素分析已被暂停。在美国印第安纳大学分析了来自Oyubari和Hobetsu地区的样本以及Horotate River序列的一部分样本。每个领域的碳同位素概况均显示出可识别的国际模式，使我们能够在国际相关框架内校准大化石的生物形象。其中，Helvetoglobotruncana Helvetica的连续出现解决了国际意义的有孔虫区域的地层范围。其他四个国际化物种还支持该地区H.helvetica区上限的地层地位。（5）将在该项目之后进行为北海道的白垩纪建立详细的年度地层学的持续努力。这样的数据收集将为利用Yezo集团作为国际按时间顺序的继承开辟道路。