| PDF: | |
| Time: | 2020 |
| Journal: | Earth Science Frontiers |
| Pages: | |
| Type: | Other |
| Author: | Xuejiao Qu,Youfeng Gao,Zhicheng Lin,Pujun Wang,Kangjun Wu |
Abstract: | The Songliao Basin and adjacent areas on one of the largest Cretaceous sedimentary landmass, is an excellent candidate for recovering a complete terrestrial sedimentary record from the top of the Upper Jurassic to the Cretaceous. However, the J/K boundary bearing areas and beds in the Songliao Basin and adjacent areas have not been confirmed until now because of discontinuous outcrops and deep burial depth. It is important to note that the division and correlation of terrestrial J/K boundary is a complex issue with no quick solutions. A set of framework characteristics of correlation needs to be devised. In this report, we discussed the framework characteristics of the J/K boundary correlation in the Songliao Basin and adjacent areas and summarized the basis of tectonic setting, magmatic events and biotic macroevolution from the Late Jurassic to the Early Cretaceous. The region west and south of the Songliao Basin has a post-collision extensional setting related to the closure of the Mongol-Okhotsk Ocean in the Jurassic, and an extensional setting in the Cretaceous caused by continental crust thickening and delamination related to the thrusting from north to south. The Songliao Basin was in a post-collision orogeny setting related to the closure of the Mongol-Okhotsk Ocean in the Jurassic, and in an extensional setting in the Cretaceous caused by plate reorganization involving the northern and eastern active continental margins. The region east of the Songliao Basin was in a strike-slip setting from the Late Jurassic to the Early Cretaceous. The Yanliao and Jehol Biotas are two big fossil groups representing the Jurassic and the Cretaceous, respectively. The Jurassic palynological assemblage is dominated by gymnosperm pollens with high abundance of Classopollis, while the Cretaceous one is dominated by bisaccate pollens of conifers with low abundance of Classopollis. The Tuchengzi Formation in northern Hebei-western Liaoning, the Donganzhen Formation in Raohe and Dongrong Formation in Suibin are the most probable J/K boundary bearing beds. The J/K boundary may also present in the Daxinganling Manketouebo Formation, the Changjiaweizi Fault Depression and the area between the Changjiaweizi Fault Depression and Daxinganling. |