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Paleozoogeographical study of Cenozoic molluscan fauna in Japan

日本新生代软体动物群的古动物地理学研究

基本信息

批准号：
62540601
负责人：
ITOIGAWA Junji
金额：
$ 0.83万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-62540601/
关键词：
Paleozoogeography Molluscan fossil Fossil assemblage Oligocene Miocene Pliocene 新生代軟体動物

项目摘要

1. Distribution of tropical molluscan assemblages in Middle Miocene is analyzed. The assemblages consist of mangrove swamp elements and others. They distribute from south to Niigata-Yamagata area and are typical in Yatsuo, Toyama and Bihoku, Okayama-Hiroshima. Similar temperature condition is seen beween present Iriomote and Middle Miocene Toyama.2. In Southwest Japan, two faunas, the lower, the Akeyo and the upper, the Kurosedani faunas, are recognized in the early to middle miocene. The ages of the two faunas ale 18 to 16 Ma and 16 to 15 Ma, respectively. The Kurosedani includes typical tropical element spement species of molluscs. The Akeyo which consists of subtropical elements differs from the Kurosedani lacking Tropical species. tropical, subtropical and temperate paleozoogeographical divisions are recognized in Middle Miocene of the Jananese Islands.3. Molluscan faunas of the Kakegawa and Ogasa groups are studied. Remarkable change from the sublittoral fauna in northwest to the bathyal one in southwest is recognized. Temporal change of species and assemblages indicates Grade I, II and III changes of Itoigawa(1988).4. The idea of grade in molluscan fauna distribution in time and space shown by Itoigawa(1988) is checked. Molluscan faunas of Oligocene and Miocane in various localities are compared and the grade is clearly recognized.

1.分析了中中新世热带软体动物组合的分布。这些组合由红树林、沼泽等元素组成。它们从南部分布到新形-山形地区，在富山的Yatsuo和冈山-广岛的Bihoku是典型的。现代伊里奥莫特与中中新世东洋之间存在相似的温度条件。在日本西南部，在中新世早期到中期，发现了两个动物群：下部的Akey o动物群和上部的Kurosedani动物群。两个动物群的年龄分别为18~16 Ma和16~15 Ma。Kurosedani包括典型的热带成分软体动物种类。由亚热带成分组成的Akey o有别于缺乏热带物种的Kurosedani。热带、亚热带和温带古地理分区在日本群岛的中中新世被识别出来。研究了Kakegawa群和Ogas a群的软体动物动物群。西北部由浅海相动物群向西南半深海相区系明显转变。物种和组合的时间变化表明Itoigawa(1988)的I、II和III级变化。对Itoigawa(1988)提出的软体动物区系时空分布等级的观点进行了验证。对不同地区的渐新世和中新世软体动物群进行了对比，明确了其等级。