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    河南省(华北型)早寒武世沉积环境演化及其痕迹化石组合

    EVOLUTION OF NORTH CHINA-TYPE EARLY CAMBRIAN SEDIMENTARY ENVIRONMENTS AND TRACE FOSSIL ASSEMBLAGES IN HENAN PROVINCE

    • 摘要: 到目前为止本省内早寒武世尚未发现有梅树村期和筇竹寺期沉积,仅有沧浪铺期和龙王庙期沉积存在。在济源—博爱—武陟一线以南地区有沧浪铺阶辛集组、朱砂洞组和龙王庙阶馒头组。该线以北只有龙王庙阶辛集组和馒头组。辛集组是个受特定环境控制的穿时地层单元。
      早寒武世沧浪铺早—中期(辛集组)沉积环境是潮下浅水陆棚和滨岸潮下带、滨岸潮坪潮间带。沧浪铺中—晚期(朱砂洞组)沉积环境是滨岸碳酸盐潮坪缓坡—潮间—潮上蒸发坪和潮间蒸发岩洼地以及潮下碳酸盐浅水缓坡。龙王庙期(馒头组)沉积环境是滨岸碳酸盐岩潮坪缓坡和潮下碳酸盐岩浅水缓坡。
      早寒武世痕迹化石主要产于三个层位,可分为H-T组合和L-B组合。前者为潮下浅水陆棚风暴环境痕迹组合,后者为潮间—潮上低能泥坪环境痕迹组合。
      早寒武世痕迹化石共11属(1新属)、16种(1新种、1相似种、10未定种)。

       

      Abstract: Except the Canglangpuian and Longwangmiaoian (Early Cambrian) sediments, no the Meishucunian and Qiongzhusian sediments have been noticed up to now in Henan Province. For instance, the Xinji and Zhushadong Formations (Canglangpuian) and the Mantou Formation (Longwang-miaoian) are distributed over the region south of the Jiyuan-Bo'ai-Wuzhi zone, whereas in the region north of it the Xinji and Mantou Formations (Longwangmiaoian) occur. It is clear that the Xinji Formation is a diachronous stratigraphic unit formed in a specific environment.
      The evolution of the Early Cambrian sedimentary environments in the study area may be generalized as follows. The early and middle Canglangpuian (Early Cambrian) Xinji Formation was de-posited in the subtidal shallow-water shelf and littoral tidal flat-subtidal zones,and the littoral tidal flat-intertidal zone;the middle and late Canglangpuian Zhushadong Formation was confined to the littoral carbonate tidal flats-ramps-intertidal and supratidal evaporative flats,intertidal evaporatic depressions and subtidal carbonate shallow-water ramps,and the Longwangmiaoian Mantou Formation was laid down in the littoral carbonate tidal flats-ramps and subtidal carbonate shallow-water ramps.
      The Early Cambrian trace fossils in the region occur dominantly in three horizons,including H-T and L-B assemblages, The former represents the trace fossil assemblages in the shallow-water shelf storm environments, whereas the latter represents those in the intertidal-supratidal low-energy mud-flat environments.
      11 genera and 16 species of trace fossils are described in detail in this paper.

       

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