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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）通过对大型化石产状的测量和仔细调查，绘制了日本北海道Tomamae町Kotanbetsu的沿着Horotate川约2公里的详细平面图（1/1000）。还在大夕张、霍别和哈博罗地区绘制了1/5000比例的平面图。在调查期间采集了泥岩样本，并在这些平面图中注明了地点。（2）在沿着Horotate河沿岸，大型化石没有显示出丰富的产出，但鉴定出区域重要的年龄指示种Inoceramus hobetsensis的连续出现。它使我们能够详细地划定本种的地层分布。（3）由于我们希望分析的一个研究所的机器故障，对Horotate河序列中大部分样品的碳同位素分析已经暂停。在美国印第安纳州大学对大夕张和保别地区的样品以及部分Horotate River层序样品进行了分析。（4）保别地区浮游有孔虫包括多种年龄指示种。其中，Helvetoglobotruncana helvetica的连续出现解决了国际重要有孔虫带的地层范围。另外四种广布种也支持了该地区H.helvetica带上限的地层位置。（5）本项目结束后，将继续努力建立北海道白垩纪的详细年代地层。这种数据收集将为利用Yezo集团作为国际时间顺序标准继承开辟道路。