四川洪雅联合地区芦山组地层的发现及生物组合特征

本文在四川洪雅联合向斜原白垩系灌口组地层中新发现了古近系芦山组地层,并详细描述了洪雅联合地区芦山组实测地层剖面。结合前人研究资料讨论了川西地区芦山组的空间分布、岩性组合特征及沉积环境。根据化石组合及分布规律,在芦山组地层中划分出一个介形虫组合带(Pinnocypris-Limnocythere-Ilyocypris组合带)和两个轮藻组合带(Gyrogona qianjiangic-Obtusochara jianglingensi组合带及Maedlerisphaera chinensis-Obtasochara brevicylindrica组合带),据此推断川西地区芦山组的地质时代为晚始新世-中渐新世。

The discovery of the Palaeogene strata and their fossil assemblages in the Lushan Formation, Lianhe region, Hongya, Sichuan

The Palaeogene strata have been distinguished in the previously defined Cretaceous Guankou Formation strata in the Lianhe syncline in Hongya,Sichuan. The spatial distribution,lithologic associations and sedimentary environments are discussed on the basis of measured stratigraphic sections in this study and the previous data. The fossil assemblages include one ostracod assemblage zone Pinnocypris-Limnocythere-Ilyocypris and two charophyte assemblage zones Gyrogona qianjiangic-Obtusochara jianglingensi and Maedlerisphaera chinensis-Obtasochara brevicylindrica. It can be deduced from the fossil assemblages cited above that the geological ages of the Lushan Formation may be traced back to the late Eocene to the middle Oligocene.