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

Evolutionary paleoecology of the Cretaceous brackish-water bivalves of southwest Japan, and the origin of the Modern Evolutionary Fauna

日本西南部白垩纪咸水双壳类的进化古生态学和现代进化动物群的起源

基本信息

批准号：
16540426
负责人：
KONDO Yasuo
金额：
$ 2.3万
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：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16540426/
关键词：
brackish water Cretaceous Bivalve southwest Japan paleoecology salinity sedimentary cycle

项目摘要

Composition of brackish-water fossil assemblages and stratigraphy and sedimentary facies of the Cretaceous in southwest Japan were investigated. Study are includes katsuura area in Tokushima Prefecture, Yuasa area in Wakayama Prefecture and Tanoura coast in Kumamoto Prefecture. In these areas, the Cretaceous sedimentary successions yielding brackish-water bivalves, consist of thick sandstone of tidal channel origin overlain by finer sediments occasionally displaying wavy- and flaser bedding indicationg tial current. Habitats of brackish-water bivalves were reconstructed in relation to the cyclicity originated from tidal channel formation.Detailed paleoecological analysis was conducted in Tatsugatani section in Katsuura area. In-situ preserved brackish-water bivalves were identified firstly in this study for Isodomella shiroiensis, Costocyrena radiatostriata, Tetoria sanchuensis, Pulsidis sp.aff.nagatoensis and Pharella sp. Five associations, comprising Crassostrea, Ostrea-Pulsidis, Ost … More rea Pyrgurifera, Isodomella-Pharella and Costocyrena-Ostrea Associations, were identified, on the basis of the relative abundances of the constituent species and in-situ preserved species The most common are Costocyrena-Ostrea Association, consisting mainly of infaunal bivalve, Costocyrena radiatostriata, along with epifaunal Ostrea sp. The ratio of individuals of infaunal bivalves is highest, and the habitat is interpreted as most unstable, being characterized by frequent erosion and deposition. In contrast, Crassostrea Associations are mostly monospecific associations, consisting of epifaunal Crassostrea sp.having elongated and flat shell. The habitat of this association is interpreted as stable substrate with relatively high salinity, probably of meso- and brachyhaline.Formerly, brackish-water benthic associations have been understood in terms of salinity regime, from oligohaline, mesohaline and brachyhaline. However, our study indicates that physical factors such as substrate unstability, such as erosion and deposition acted as a serious limiting factor, being similar to those in marine benthic associations. Less

研究了日本西南部白垩纪的咸水化石组合组成、地层和沉积相。研究对象包括德岛县胜浦地区、和歌山县汤浅地区和熊本县田浦海岸。在这些地区，白垩纪沉积序列产生咸水双壳类，包括潮汐通道成因的厚砂岩，上覆有偶尔显示波浪状和扁平层理指示水流的较细沉积物。根据潮道形成的旋回性，重建了咸水双壳类的化石，并对胜浦地区辰谷剖面进行了详细的古生态分析。本研究首次鉴定出原位保存的咸水双壳类为白氏等壳藻（Isodomella shiroiensis）、辐射条纹肋壳藻（Costocyrena radiatostriata）、三中Tetoria sanchuensis、长户Pulsidis sp.aff.nagatoensis和Pharella sp ...更多信息根据组成种和原位保存种的相对丰度，将其划分为三个群丛：Pyrguifera、Isodomella-Pharella和Costocyrena-Ostrea群丛。最常见的是Costocyrena-Ostrea群丛，主要由底栖双壳类、辐射条纹Costocyrenaradiatostriata和沿着的是表栖牡蛎Ostrea sp.以频繁的侵蚀和沉积为特征。相比之下，牡蛎群丛大多是单种群丛，由具有细长和扁平外壳的表层动物组成。该协会的栖息地被解释为稳定的基板相对较高的盐度，可能是中盐和brachyhaline. Forward，咸水底栖生物协会已被理解的盐度制度，从寡盐，中盐和brachyhaline。然而，我们的研究表明，物理因素，如底质的不稳定性，如侵蚀和沉积作为一个严重的限制因素，类似于海洋底栖动物协会。少