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

Landform evolution and sedimentary environment of the riverine coastal plain around the Holocene/Pleistocene boundary.

全新世/更新世边界沿河滨海平原地貌演化与沉积环境.

基本信息

批准号：
07680185
负责人：
UMITSU Masatomo
金额：
$ 1.47万
依托单位：
NAGOYA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07680185/
关键词：
Riverine coastal plain Late Quaternary sediment Sealevel change Holocene Pleistocene Holocene boundary

项目摘要

This research aims to clarify the landforms and sedimentary environments of the riverine coastal plain in the period around the Holocene/Pleistocene boundary.Detail analysis of the Holocece/Pleistocene boundary of the sediments was done on the Nobi plain. Regional defferences of the facies in the latest Pleistocene can be seen in the sediments. The differences are considered to be caused by the elandforms and sedimentary environments of each location at that time. Thick sandy sediments can be seen in the delta front, and the places where the thick oyster shell bed can be seen in the tidal flat at that time. Furthermore, in the places of the flood plain, fluvial muddy sediments develop widery. Shallow dissected valleys and channel fills are also seen in the contact of the Holocene/Pleistocene boundary. These regional differences of the sediments are the result of the slow transgression and the difference of the location in the deltas at that time.In the small riverine coastal plains at the Tsugaru and the Abashiri, muddy Holocene sediments cover the latest Pleistocene sediments which are consisted of sand or sandy gravels. Peat layrs are occasionaly seen in the lowest part of the muddy sediments. This shows that the sedimentary environment of the Pleistocene/Holocene boundary in these lowlands in mainly flood plain, and the abrupt change to the marshy condition can be seen in some places.

本研究旨在明确全新世/更新世边界附近的河滨平原地貌和沉积环境。对浓尾平原全新世/更新世边界沉积物进行了详细分析。沉积物中可以看出晚更新世相的区域差异。认为这种差异是由当时各地的地形和沉积环境造成的。三角洲前缘可见厚厚的砂质沉积物，当时的滩涂中可见厚厚的牡蛎壳床的地方。此外，在河漫滩地区，河流泥质沉积物广泛发育。在全新世/更新世边界的接触处还可以看到浅层切割的山谷和河道充填物。沉积物的这些区域差异是缓慢海侵和当时三角洲位置差异的结果。在津轻和网走的小型河流沿岸平原，泥质全新世沉积物覆盖了由砂或砂砾石组成的最新更新世沉积物。在泥质沉积物的最低部分偶尔可以看到泥炭层。这表明这些低地更新世/全新世边界的沉积环境主要为洪泛平原，部分地区出现了向沼泽状态的突变。