吉林省延吉盆地早白垩世中晚期地层

THE MIDDLE——LATE EARLY CRETACEOUS STRATA IN YANJI BASIN, JILIN PROVINCE

吉林省的延吉盆地实际上由铜佛寺和大拉子(智新)两盆地构成。本文详细讨论了发育于上述盆地下白垩统铜佛寺组和大拉子组的层序及其沉积特征,并与世界上有关地层进行了对比。

This article deals with the stratigraphic sequence of the middle-upper part of Lower Cretaceous, Yanji basin, and its lithology and rock facies characteristics, and then, discusses the depositional environment, the characteristics of fossil assemblage and the correlation with other related strata.The Lower Cretaceous in the basin includes, the lower Tongfosi Formation and the upper Dalazi Formation.The former consists of yellow conglomerate, sandstone and shale, with a total thickness of more than 2830m.yielding abundant fossil plants.They are: Filices: Acanthopteis gothani Szes Onychiopsis elongata Yokoya-ma. O psilotoides Seward; Ruffordia goepperti Seward. Cladophlebis cf brownia-na (Duuker) Seward and Cycadopsida: Neozamites verchojanesis Vach.;as well as Ginkgopsida Coniferae and a few of Angiospermae, Reptilia,Bivalvia and Gastropoda etc. This assemblage is evidently of middle Early Cretaceous, i.e. Barremian-Aptian, in age.The Dalazi Formation consists of gray-yellow conglomerate, sandstone and black shale, intercalated with oil shale beds, the total-thickness being more than 2000m. This Formation contains abundant fossil plants, they have the characteristics of extreme development of Coniferae: Brachyphyllum parceramosum Fontaine. Monica (changlingia) tholistoma Chow et Tsao. M .papillose Zhou et Cao; Frenclo-psis elongata Chow et Tsao: Suturovagia intermieia Chow et Tsao;Cupressinocla-dus elegans Chow etc. Besides these there are a lot of angiosperms, as well as Sphe-nopsida, Filices, Cycadopside, Ginkgopsida and Pisces, Bivalvia, Gastropoda, Bran-chiopoda, Ostrocoda, Insecta remains.The characteristic of this assemblage is the existence of a large of number of an-giosperms.They are 'Anodromoda'Parlaterii Heer. Rogersia angustifolia Fontaine etc. It is of late Early Cretaceous,i.e. the Albian in age.