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本文详细描述了重庆石柱漆辽剖面奥陶系达瑞威尔阶(Darriwilian)牯牛潭组至凯迪阶(Katian)宝塔组的牙形刺序列及其对比。牙形刺序列由上而下可分为:宝塔组Hamarodus brevirameus生物带和Amorphognathus superbus生物带;大田坝组的Baltoniodus alobatus,Baltoniodus variabilis和Yangtzeplacognathus jianyeensis生物带;牯牛潭组的Yangtzeplacognathus crassus生物带和Lenodus variabilis生物带。其中Hamarodus brevirameus生物带至Baltoniodus alobatus生物带上部为凯迪阶,B.alobatus生物带下部至Yangtzeplacognathus jianyeensis生物带上部为桑比阶(Sandbian),而Yangtzeplacognathus jianyeensis生物带下部,Yangtzeplacognathus crassus生物带和Lenodus variabilis生物带归入达瑞威尔阶。根据文中所识别的牙形刺序列,该剖面显然缺失了达瑞威尔阶中上部的牙形刺生物带如Pygodus serra生物带(即Yangtzeplacognathus protoramosus和Y.foliaceus生物带),Eoplacognathus suecicus和Dzikodus tablepointensis生物带。因此,在重庆石柱漆辽剖面奥陶系牯牛潭组和大田坝组之间的地层是不连续的,存在一明显的沉积间断,缺失了相当于牯牛潭组标准剖面中上部的地层(达瑞威尔阶中上部)。而这一沉积间断所发生的时间正好与达瑞威尔中晚期全球海平面下降相吻合。
In this paper, the conodonts of the Ordovician Darriwilian 牯NiuTan Formation to Katian Pagoda in the Zhiliao section of Shizhu, Chongqing are described in detail. The conodonts can be divided into upper and lower belts: Hamarodus brevirameus and Amorphognathus superbus belts in Pagoda group; Baltoniodus alobatus, Baltoniodus variabilis and Yangtzeplacognathus jianyeensis belts in Datianba group; Yangtzeplacognathus crassus belts and Lenodus variabilis Biological band. Among them, the upper band of Hamarodus brevirameus to Baltoniodus alobatus is Kaidi, the upper part of B.alobatus to Yangtzeplacognathus jianyeensis is the band of Sandbian, while the lower part of Yangtzeplacognath jianyeensis belts, Yangtzeplacognathus crassus and Lenodus variabilis Belongs to the Daruiweier order. Based on the conodont sequence identified in this paper, the profile clearly lacks the conodonts such as the Pygodus serra (ie, the Yangtzeplacognathus protoramosus and Y.foliaceus) zygotes from the upper middle of the Daruiweier order, the Eoplacognathus suecicus and Dzikodus tablepointensis Biological band. Therefore, the strata between the Ordovician Qiu Nitan group and the Datian group are not continuous in the Zhiliao section of Shizhu, Chongqing with a distinct depositional discontinuity, missing the middle and upper strata corresponding to the standard section of the Qiu Nitan group Upper Will rank). The timing of this depositional discontinuity coincided well with the downtrend in Darwin’s mid-late global sea level.