Late Triassic-Middle Jurassic Stratigraphic Succession in theNiuyingzi Basin, Lingyuan County, Western Liaoning and the Correlation of Regional Stratigraphic Sequences in the Yanliao Region

This paper discusses the correlation of the regional stratigraphic sequences on the basis of renewed Late Triassic-Middle Jurassic stratigraphic sequences and their ages in Niuyingzi basin of Lingyuan County, western Liaoning Province. The late Upper Triassic Dengzhangzi Formation composed of slump carbonate breccia serves as the record of the Indosinian orogeny, and is correla-table with both Xingshikou Formation in western Beijing and northern Hebei and Yangcaogou Formation (Kuntouboluo Formation) in Beipiao of western Liaoning. The Lower Jurassic Shuiquangou Formation is correlatable with both Nandaling Formation in western Beijing and northern Hebei and Xinlonggou Formation in Beipiao of westeren Liaoning. Dating of the volcanic rocks from those formations yields the similar result. The lower coal-bearing Guojiadian Formation of early Middle Jurassic has similar plant assemblages to both Shangyaopo Formation in western Beijing and Middle Xiahuayuan Formation in northern Hebei as well as to Middle-Upper Bei-piao Formation of Beipiao in western Liaoning. The conglomerate member of middle Middle Jurassic Guojiadian Formation, as the product of the major episode of the Yanshanian movement, is correlatable with both Longmen Formation in the Western Hills, Beijing, and Upper Xiahuayuan Formation of Xiabancheng in northern Hebei and Haifanggou Formation of Beipiao in western Liaoning. Dating of the basement of the middle-late Middle Jurassic Lanqi Formation in western Liaoning gives a zircon SHRIMP U-Pb age of 158±1 Ma, which is similar to that of Tiaojishan Formation in both western Beijing and northern Hebei. The remarkably different sedimentary records of Triassic-Middle Jurassic basins in the intraplate Yanshanian orogenic belt have similar evolutionary characteristics.