二连盆地西部赛汉塔拉组轮藻化石及其时代意义

Charophyte Fossils from the Saihantala Formation in Western Erlian Basin

报导了首次发现于二连盆地西部白音查干凹陷井下剖面赛汉塔拉组的轮藻化石4属8种,包括Atopochara restricta,Mesochara symmetrica,M.stipitata,Aclistochara mundula,A.daerqiensis sp.nov,A.caii,A.subquadrularia,Obtusochara maedleri。其中建立新种1个。根据轮藻化石的特征、地质分布以及现生轮藻化石的生境分析,说明化石赋存的地层的时代为早白垩世阿普第晚期-阿尔必期,很可能属阿普第晚期,沉积环境为较宁静的河湾等浅水,为区内油气勘探中赛汉塔拉组地层划分与对比以及沉积环境分析提供了古生物学的证据。

The fossil Charophytes reported here were collected from the Saihantala Formation in Da-5 well, Western Erlian Basin, Inner Mongolia. They comprise Atopochara restricta, Mesocham sym-metrica, M. stipitata, Aclistochara mundula,A.daerqiensis sp. nov. , A. caii, A. subquadrularia and Obtusochara maedler, with altogether 4 genera and 8 species. According to regional distribution of these fossils, it is considered as Early Cretaceous Upper-Ap-tian to Albian, probably Upper-Aptian in age. The similar fossil assemblage was first reported from the Upper-Aptian or Albian in Western Europe. In China, it is similar to discovered from the Upper Quantou Formation in Songliao Basin, NE China, which Is considered as Albian in age.