Comparison of the Panthalassa and the Paleo-Tethys based on radiolarian analysis

本研究的目的是在放射虫分析的基础上，比较二叠纪至三叠纪Panthalassa和古特提斯的古海洋环境。研究资料收集：(1)日本西南部米诺地体的层状燧石，(2)中国南部扬子地体的碎屑岩和酸性凝灰岩，(3)中国西南部长宁—孟连地体的层状燧石，(4)中国南部云凯地体的层状燧石。Panthalassa沉积物（Mino Terrane）的二叠纪放射虫动物群显示出高度的多样性，与太平洋低纬度深海沉积物的近代放射虫动物群相当。华南地区（扬子台地和云开地）的二叠系放射虫区系位于古梯梯纪的东缘，种类较少。典型的古特提斯（长宁-孟连地）的起源也不多样。这些特征表明，尽管存在低纬度的海底沉积物，但泛海期与古特提斯期的古海洋环境存在较大差异。然而，根据两个古海洋放射虫的区系变化，认为两个古海洋都经历了二叠纪/三叠纪界线的全球环境变化。

The object of this research was to compare the paleoceanic environment of the Panthalassa and the Paleo-Tethys during Permian to Triassic time based on radiolarian analysis. Materials of this research were collected from (1) bedded cherts of the Mino Terrane in Southwest Japan, (2) clastics and acidic tuff of the Yangzi Platform in South China, (3) bedded cherts of the Changnin-Menglian Terrane in Southwest China, and (4) bedded cherts of the Yunkai Terrane in South China.The Permian radiolarian fauna from the Panthalassa deposites (the Mino Terrane) indicates high diversity which is comparable with recent radiolarian fauna from the low latitudinal deep sea sediments of the Pacific Ocean. The Permian radiolarian faunas from South China (the Yangzi Platform and the Yunkai Terrane), which situated in the eastern margin of the Paleo-Tetys, are not so diverse. The founa fo the typical Paleo-Tethys (the Changnin-Menglian Terrane) is not also diverse. These features suggest that the paleoceanic environment was considerably different between the Panthalassa and the Paleo-Tethys in spite of the low latitudinal bottom sediments. However, on the basis of the radiolarian faunal change in both paleoceans, it is considered that both paleoceans suffered the global environmental change through the Permian/Triassic boundary.