Subdivision Of The Jiufotang Formation And Stratigraphic Analysis In Kazuo Basin

Kazuo basin is Late Mesozoic era rift basin in the west of Liaoning, in which lower cretaceous the Jiufotang formation is the filling stratum. In view of these facts that there are many subdivision plans of the Jiufotang formation and other related issues, the authors measured more than ten sections which was 106km in all. Using the basic principles of lithostratigraphy and sedimentology, five tuffaceous rocks marker beds or bed group marker are distinguished from the Jiufotang formation in the Kazuo basin. The Jiufotang formation is subdivided into four members bounded on the top of Marker Bed or Bed Group Marker 1, 2, 4, 5. On the basis of facies mark and spatial allocation analysis, such as the color, structure, primary sedimentary structure of field outcrops, and also analysis of the laboratory, three sedimentary facies containing lake facies, braided river delta facies and fan delta facies are recognized from Jiufotang formation finally. Lake is oil shale of Jiufotang formation main sedimentary environment.