| Research Abstract |
This Research work was carried out for a radiolarian biostratigraphic analysis of the upper Paleozoic group in the eastern part of the Yangtze Block in China, particularly, in Anhui Province (around Chaohu Lake, Yixian and Jinxian) and Jiangsu Province (eastern suburb of Nanjing).
Following three new results are obtained.
1. Late Permian radiolarians such as Albaillellasp. cf. A. xiaodongensis, and Follicucullus sp. cf. F. orthogonus were detected from siliceous mudstone of the lower part of the Dalong Formation at the Pingdingshan section in the Chaohu area, Anhui Province. The age of the lower part of the Dalong Formation in the Chaoku area is, therefore, probably Wujiapingian (early late Permian), although the Dalong Formation has been commonly considered to be Changxingian (late Late Permian). (Kametaka, M., Nagai, H., Zhu, S. and Wu, C., 1999)
2. There is a peculiar type of bedded siliceous rock (Nectic Chert) intercalated in the Gufeng Formation of the Lower Permian in the northern Chaohu area, Anhui Province. The rock contains many rhombic and irregular cavities surrounded by siliceous cement consisting of microquartz. SEM observation, the chemical and X-ray analyses of the rock suggest that this siliceous rock originated from carbonates, such as dolomitic limestone, the pores correspond to the casts of euhedral dolomite rhombus contained in dolomitic limestone, which were dissolved out in a later stage of diagenesis. (Zhu, S., Nagai, H., Kametaka, M. and Wu, C., 1999)
3. New radiolarian morphotypes were found from the siliceous mudstone of the Upper Permian Dalong Formation, eastern suburb of Nanjing. Its external form is conical or spindle similar to that of Mesozoic Archaeodyctiomitra, but is different from it by having strong, wide and less costae by having shell with relict pores. (Nagai, H., Yang, Q. and Wang , Y., 1999)
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