滇东北永善县奥陶纪牙形石的鉴定及其对地层时代的约束

    Identification of Ordovician conodont in Yongshan County of northeastern Yunnan Province and its significance of stratigraphic age constraint

    • 摘要: 首次在滇东北永善县奥陶纪地层中获取牙形石,填补了这一地区奥陶纪地层牙形石资料的空白。该区牙形石鉴定及笔石等资料表明,永善县奥陶纪地层缺失桐梓组、红花园组。湄潭组属下奥陶统,十字铺组属中—下奥陶统,宝塔组属中—上奥陶统。牙形石特征与扬子地区奥陶纪地层相似,但也有自身的特点,主要表现在宝塔组缺失带化石,是样品采集不足还是沉积环境的差异,有待进一步的研究。

       

      Abstract: The conodonts obtained from the Ordovician strata for the first time in Yongshan County of northeastern Yunnan province fills in the blank of conodont data in this area.These data show that the Ordovician strata are lack of Tongzi Formation and Honghuayuan Formation.The Meitan Formation belongs to the Lower Ordovician, the Shizipu Formation belongs to the Middle-Lower Ordovician, and the Pagota Formation belongs to the Middle-Upper Ordovician.The conodonts are similar to the Ordovician strata in the Yangtze area, but they also have their own characteristics, which are mainly reflected in the missing zone fossils in the Pagota Formation.The lack of zone fossils in the Pagota Formation is due to insufficient sample collection or differences in sedimentary environment, which needs further study.

       

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