Cyclostratigraphy of the Upper Jurassic—Lower Cretaceous and Basin Evolution Mechanism in the North Yellow Sea Basin

ABSTRACT The time reflected by the Milankovitch cycle is of great significance for determining the depositional time frames of strata. We utilized GR log curves to analyse the cyclostratigraphy of Sequence 1–Sequence 8. The results show that dating of sequences 1 through 4 depositional timeframes as follows: 148–145, 145–143, 143–141 and 141–140 Ma. According to the isochronity of sequence interface, it is speculated that the top boundary ages of sequence 5 through sequence 7 may be 134, 128 and 123 Ma, and sequence 8 may end at least after 118 Ma. During 148–143 Ma, the North Yellow Sea Basin was affected by the extension and collapse of the Sulu Orogenic Belt. During 143–140 Ma, the basin underwent a right‐lateral movement from transtension to transpression due to the strike‐slip activity of the Tanlu Fault and the continuous collapse of the Sulu Orogenic Belt. The basin expanded to the northeast and southeast. Until the 140 Ma, the basin was affected by the strike‐slip activity to the maximum, and the tectonic inversion occurred in the basin. During the 140–118 Ma, the Tanlu Fault gradually changed from strike‐slip to normal fault, and the basin also developed and expanded gradually.