【摘要】 燕山地区土城子组分布广泛,顶底清晰,是本区最具特色的岩石地层单位之一。区域地质对比研究表明,燕山西部土城子组与燕山中东部土城子组在地层、时代上有较大的不同,西部盆地中髫髻山组火山岩不发育或很少发育,土城子组在地层划分上常包含九龙山组或髫髻山期火山岩,时代为中晚侏罗世(J2—J3);东部盆地普遍发育髫髻山组火山岩浆或火山-沉积地层,土城子组划分与层型剖面一致。古生物化石和同位素年龄研究表明:土城子组时限在156~139Ma之间,属于晚侏罗世—早白垩世。土城子期盆地沉积的不对称性,相分布特征,古水流等指示其形成在一个挤压作用下的陆内火山-沉积盆地环境。更多还原

【Abstract】 The Tuchengzi Formation is widespread in the Yanshan intracontinental orogenic blet of North China, which is one of the most typical lithostratigraphy units clearly constrained by the low and upper boundaries. Base on the regional geological correlationship, our works show that Tuchengzi Formation’s age and stratigraphy are much different from west to east in the Yanshan belt. In the western basin, Tiaojishan volcanic units is very rare or few, Tuchengzi Fm. including Jiulongshan deposits and Tiaojishan volcanic units and its age is Middle-Late Jurassic;on the contrary in the eastern basin Tuchengzi Fm. is same as its stratotype section and its age is Late Jurassic-Early Cretaceous, Tiaojishan volcanic units is rich and very widespread,. Fossils and Isotopic dating constrain the Tuchengzi Fm.range from 156 to 139 Ma, assigned to Late Jurassic-Early Cretaceous. The character of the asymmetric fillment, E-W distributions of sedimentary facies and paleocurrentwater indicate that the Tuchengzi stage deposition was controlled by synsedimentary thrusting on the north sides of the basins. The Late Jurassic Early Cretaceous basins were generated under the compressitine condition from the north to the south, belonging to the interior compressional volcanoic sedimentary basin in the intracontinental Yanshan orogenic belt.更多还原