不宜笼统地把钙质超微化石都当作海侵或海陆过渡相烃源岩的标志

It is Inadvisable to Regard All Calcareous Nanofossils in Hydrocarbon Source Rock as Mark for Hydrocarbon Source Rock of Marine Transgression or Paralic Origin

在我国西北和东北15个地区新生代一现代陆相成化湖沉积物中,发现钙质超微化石Coccolithus、Retic-ulofenestra等10个属。除有一部分属于再沉积来源外,多数为原地沉积。其特点是属种分异度低、丰度低,常与陆相喜盐水生物共生。尽管第四纪-现代陆相咸化湖沉积中发现的属种多数是同期海相中的常见类型,但是两者在丰度、分异度和共生生物方面有明显区别。因此,不能把所有钙质超微化石都当作海侵或海陆过渡相烃源岩的标志。

Ten genera of calcareous nanofossils such as Coccolithus and Reticulofenestra have been discovered in terrestrial sediments of Cenozoic-present salinized lakes from fifteen places in northwest and northeast China. Most of these fossils are sedentary; only a small are reworked. The characteristics of them are as follow:low variation;low abundance; frequently coexist with terrestrial halopilic hydrobioses. Although most of calcareous nanofossils found in terrestrial sediments of Cenozoic-present salinized lakes are the same class as some common marine types at the same time, differences in variation, abundance and coexisting hydrpbioses are distinct. Not all calcareous nanofossils in hydrocarbon source rock are identification of hydrocarbon source rock with marine transgression or paralic origin.