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我国西藏南部海相白垩系含有较丰富的钙质超微化石。文中着重研究岗巴地区两个剖面 (即剖面A ,B)Albian Santonian钙质超微化石的分布。根据标志种的存在 ,识别出 5个初现面事件 ,相应地建立 6个钙质超微化石带 ,自下至上是Prediscosphaeracretacea带 ,Eiffellithusturriseiffeli带 ,Lithraphiditesacutum带 ,Gartneragoobliquum带 ,Quadrumgartneri带 ,Lucianorhabduscayeuxii带。同时 ,通过洲际对比 ,建议以G .obliquum初现面作为划分本区Cenomanian和Turonian界线的标志。此外 ,Q .gartneri带和I .cayeuxii带之间缺失多个化石带 ,据此推测Turonian至Santonian期间本区可能存在沉积间断。
The marine Cretaceous in southern Tibet contains abundant calcareous nannofossils. This paper focuses on the distribution of Albian Santonian calcareous microfossils in two sections (ie sections A and B) in Gamba area. According to the existence of the marker species, five emergent surface events were identified, and six calcareous microfossils were established correspondingly. They were Prediscosphaeracretacea, Eiffellithustririseiffeli, Lithraphiditesacutum, Gartneragoobliquum, Quadrumgartneri and Lucianorhabduscayeuxii from bottom to top. At the same time, through intercontinental comparisons, it is proposed that the appearance of G.obliquum be used as a sign of dividing the Cenomanian and Turonian boundaries of the area. In addition, the absence of multiple fossil zones between the Q.Gartneri zone and the I.Cayeuxii zone suggests that there may be depositional discontinuities in this area from Turonian to Santonian.