权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

INTERNATIONAL CORRELATION OF MAGNETO-BIOSTRATIGAPHY OF JAPANESE CRETACEOUS

日本白垩纪磁生物地层学的国际对比

基本信息

批准号：
10640449
负责人：
KODAMA Kazuto
金额：
$ 0.9万
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：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640449/
关键词：
MAGNETOSTRATIGRAPHY BIOSTRATIGRAPHY UPPER CRETACEOUS HOKKAIDO POLARITY CHRON NORTHWEST PACIFIC STAGE BOUNDARY SAKHALIN

项目摘要

A series of normal and reversed polarity zones have been found from [he Upper Cretaceous sedimentary strata in Hokkaido of Japan and south Sakhalin of Russia. Combined magnetostratigraphic and biostratigraphic correlation has enabled us to assign these zones to the Late Cretaceous polarity chrons including the Cretaceous superchron.A polarity sequence in the Izumi Group in southwest Japan consists of the lowermost horizon of reversed polarity and a thick succession of normal polarity with two intervening horizons of reversed polarity. Based upon previous biostratigraphic age constraints, the Pattern of these polarity zones matches a polarity change from Chrons 33r through 31r during the early Campanian to the earliest Maastrichtian stages. Thick successions of normal polarity were recognized in the Upper Ezo Group in central Hokkaido and the Bykov Group in south Sakhalin. The normal polarity horizon of the Ezo Group is overlain by a short reversed horizon, and they yield abundant fossils of Cenomanian to Campanian age. It is thus most likely that the normal polarity can be assigned to the Cretaceous normal polarity superchron C34n and the overlying reversed zone assigned to subsequent Chron 33r in the early Campanian. The thick horizon of normal polarity in south Sakhalin is overlain by at least three zones of reversed polarity, including Chrons 33r in the early Campanian and Chrons 32r and 31r in Maastrichtian.All these reversed polarity chrons have been documented for the first time from the Cretaceous systems of the Northwest Pacific. The successive record of polarity reversals and their correlation to faunal assemblages that commonly occur in Japan and other areas in the Far East provide an integrated reference that should be of value for linking local biostratigraphic zonations in the North Pacific and serve as another basis for calibration in the quest to establish a global definition of Upper Cretaceous stage boundaries.

在日本北海道和俄罗斯库页岛南部的上白垩统沉积地层中发现了一系列正极性带和逆极性带。结合磁地层学和生物地层学对比，我们将这些带划分为晚白垩世极性年代史，包括白垩世超年代史。日本西南部泉群的一个极性层序是由最低的反极性层和厚的正极性层序以及中间的两个反极性层序组成的。根据以往的生物地层年龄限制，这些极性带的格局与坎帕纪早期至马斯特里赫特纪早期第33 ~ 31纪的极性变化相吻合。北海道中部的上鄂左群和库页岛南部的Bykov群具有较厚的正极性序列。埃佐群正极性层被短极性层复盖，具有丰富的塞诺曼-坎帕尼亚时代化石。因此，正常极性极有可能归属于白垩纪正极性超时C34n，而其上的反转带极有可能归属于晚坎帕尼亚纪33r。库页岛南部厚的正极性层被至少3个反极性带覆盖，包括坎帕尼亚早期的第33r期和马斯特里赫特的第32r和第31r期。所有这些极性颠倒的年表都是在西北太平洋的白垩纪系统中首次被记录下来的。极性逆转的连续记录及其与日本和远东其他地区常见的动物组合的相关性提供了一个综合参考，对于连接北太平洋当地的生物地层带具有价值，并可作为寻求建立上白垩纪阶段边界全球定义的另一个校准基础。