Radiolarian Analysis of Yangtze Block in South China

华南扬子地块放射虫分析

• 批准号: 09045033
• 负责人: NAGAI Hiromi
• 金额: $ 1.79万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B).
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09045033/
• 关键词: Radiolarian; Permian; Yangtze Block; Chaohu area; Eastern suburb of Nanjing City; Dalong Formation; Gufeng Formation; Nectic Chert; 安徽省; 江蘇省; 巣湖; 庵門口; 孤峰層; 下揚子地塊; 三畳紀境界; Y山

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)

本文对中国扬子地块东部，特别是安徽（巢湖、黟县、金县一带）和江苏（南京东郊）的上古生界放射虫群进行了生物地层分析。得到了以下三个新的结果：1。晚二叠纪放射虫，如Albaillellasp。在安徽巢湖平顶山剖面大龙组下段硅质泥岩中发现了cf. A. xiaodonggensis和Follicucullus sp. cf. F. orthogonus。因此，巢库地区大龙组下段的时代可能为吴家坪期（晚二叠世早期），而一般认为大龙组为长兴期（晚二叠世晚期）。（Kametaka， M., Nagai， H., Zhu， S. and Wu， C., 1999）安徽巢湖北部地区下二叠统谷峰组中嵌有一种特殊的层状硅质岩（Nectic燧石岩）。岩石中含有许多菱形和不规则的孔洞，被由微石英组成的硅质胶结物包围。岩石的扫描电镜观察、化学分析和x射线分析表明，该硅质岩石起源于白云岩等碳酸盐岩，孔隙对应于白云岩中所含的自形白云岩菱形，在成岩后期溶蚀而出。（朱，S., Nagai， H., Kametaka， M.和Wu， C., 1999）在南京东郊上二叠统大龙组硅质泥岩中发现了新的放射虫形态。其外部形态与中生代古藻相似，呈圆锥形或纺锤形，但与中生代古藻不同的是，其外壳坚固、宽，且壳体较少，有残余孔隙。（Nagai， H., Yang， Q. and Wang， Y., 1999）

项目成果

Nagai Hiromi et al.: "New radiolarian morphotypes from the Dalong Formation, east suburb of Nanjing"Palaeoworld. No.12. 85-93 (1999)

永井博美等：“南京东郊大龙组新的放射虫形态类型”古世界。

Nagai H., Yang, Q. and Wang, Y.: "New radiolarian morphotypes from the Dalong Formation, east suburb of Nanjing"Palaeoworld. No. 12. 85-93 (1999)

Nagai H.，Yang，Q.和Wang，Y.：“南京东郊大龙组新的放射虫形态类型”古世界。

Nagai H.et al.: "New radiolarian morphotypes from the Dalong Formation,east suburb of Nanjing."Palaeoworld. No.12. 85-93 (1999)

Nagai H.等：“南京东郊大龙组新的放射虫形态类型。”古世界。

Kametaka M., Nagai, H., Zhu, S., Qi, D. and Wu, C.: "Late Permian radiolarians from the Dalong Formation in the Chaohu area, Anhui Province, China"J. Earth Planet. Sci. Nagoya Univ. Vol. 46. 15-28 (1999)

Kametaka M., Nagai, H., Zhu, S., Qi, D. and Wu, C.: “中国安徽省巢湖地区大龙组晚二叠世放射虫”J.

朱 嗣昭: "種特殊類型珪質岩-浮石状燧石"高校地質学報. Vol.5. 345-350 (1999)

朱继照：“硅质岩石的特殊类型——漂浮燧石”，高中地质通报，第5卷，345-350(1999)。