發(fā)布時間：2018-06-01 14:15

  本文選題：生物地層 + 巖石地層�。� 參考：《地層學雜志》2017年04期

【摘要】：在湖北省建始縣北部細沙壩剖面志留系最上部發(fā)現(xiàn)腕足動物及幾丁類化石。腕足動物組合以華美瓦爾達貝(Valdaria lauta)為典型分子,屬于秀山動物群第二組合帶;同時根據(jù)幾丁類的組合帶延限,綜合分析確定其時代為特列奇中期,相當于秀山組上段的中部。鑒于與典型紗帽組在巖性、時代的明顯差別,鄂西地區(qū)的來鳳、咸豐、鶴峰、宣恩、恩施、建始、巴東等地的這套以往稱作紗帽組的地層改稱為秀山組為宜。建始細沙壩與桐梓韓家店、石阡雷家屯、秀山溶溪、宣恩高羅、宜昌大中壩等五地志留系對比說明,上揚子區(qū)各地志留系蘭多維列統(tǒng)的頂界是參差不齊的,其中秀山的相關地層頂界最高,桐梓和宜昌的最低。上述情況反映當時海域沉積受廣西運動的直接影響,導致地殼上升,從而海水退盡,巖層差異剝蝕強烈,此系華夏古陸向西北方向顯著擴張的結(jié)果。
[Abstract]:Brachiopods and some fossils were found in the upper part of Silurian in Xieshaba section, northern Jianshi County, Hubei Province. The brachiopod assemblage takes Valdaria lautataa as a typical molecule and belongs to the second assemblage zone of Xiushan fauna, and according to the extension limit of the assemblage zone of several species, it is determined by comprehensive analysis that its age is the middle period of Terec, which is equivalent to the middle part of the upper member of Xiushan formation. In view of the obvious difference in lithology and age between the typical Yimao formation and the typical Yimao formation, it is appropriate that the strata in the west of Hubei Province, such as Laifeng, Xianfeng, Hefeng, Xuanen, Enshi, Badong and so on, should be renamed as Xiushan formation. The comparison between Xianshixiesba and Tongzi Hanjiadian, Shipathiajiatun, Xiushan dissolving stream, Xuanen Gaoluo, Yichang Dazhong dam and other five Silurian systems shows that the top boundary of the Upper Yangzi Silurian Lando Dimension system is uneven. The top boundary of Xiushan is the highest and the lowest of Tongzi and Yichang. The above situation reflects that the sediments in the sea area were directly influenced by Guangxi movement at that time, which led to the rise of the crust, which resulted in the retreating of the sea water and the strong denudation of the difference between the strata, which was the result of the significant expansion of the Cathaysian paleocontinent to the northwest.
【作者單位】： 現(xiàn)代古生物學和地層學國家重點實驗室中國科學院南京地質(zhì)古生物研究所;中國科學院大學;北京大學地球與空間科學學院;
【基金】：國家自然科學基金(No.41472006,41521061,41530103)支持
【分類號】：P534.43

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