Lower Cretaceous Lacustrine Sedimentary Sequences of a Small Intracontinental Rift Basin in Luanping, China

The Luanping Basin is a typical continental rift basin that developed during the Middle Jurassic to Early Cretaceous in the Yanshan fold-thrust belt in Northeast China. The Yanshan fold-thrust belt, which is characterized by terrestrial sedimentation, magmatism and deformation—including multiple phases of folding and contractional, extensional, and strike-slip faulting throughout China during the Jurassic‒Cretaceous Cretaceous—was mentioned in the Chinese literature as a result of deformation episodes named the Yanshan (or Yenshan) movement, Yanshanian movement, or Yanshanian deformation (Cope, 2003; Davis et al. 1998, 2001; Dou et al. 2020; Li et al. 2003, 2007). The Luanping Basin is a small half-graben and elongated in a NE‒SW direction, approximately 40 km long and 20 km wide. Controlled by multiepisodic Yanshanian movements, the basin experienced extensional and transtensional stresses leading to a complex rifting process. Three rifting episodes were divided: the first episode occurred in the early Middle Jurassic, the second episode occurred in the middle to late Middle Jurassic, and the third episode took place during the late Jurassic to early Cretaceous. During these rifting episodes, thick nonmarine terrestrial volcanic and clastic synrift successions (~5000 m) accumulated. The synrift strata are composed of five lithologic stratigraphic units: the Jiulongshan, Tiaojishan, Houcheng, Zhanjiakou and Xiguayuan Formations.