Geological control of the eastern Great Wall: Mountain-basin relationships in the eastern North China Craton

Abstract

The E–W trending Yanshan belt, an intraplate fold-thrust belt located in the northern North China Craton, has experienced several episodes of Mesozoic deformation, which resulted in the widely distributed magmatism and mountain-basin tectonics that completely re-shaped the topography of the eastern North China Craton. The eastern part of the famous Chinese Great Wall was built on the high range of the southeastern Yanshan mountain belt juxta-posed to the plain, which directly relates to the Bohai Bay basin. Our study focuses on which tectonic processes created such mountain-basin couple in Mid-Late Mesozoic times. The U-Pb LA-ICP-MS dating of zircons yield ages of 114 to 201 Ma for various granites and 115 to 116 Ma for volcanic rocks from Yixian and Jiufotang Fms. The detrital zircons from the Lower Cretaceous sandstones yield four age groups of 2587 to 2460 Ma, 2222 to 1828 Ma, 297 to 190 Ma and 187 to 100 Ma, which are all sourced from the Qinglong and surrounding areas and indicating that the Qinglong area started to uplift after the Middle Jurassic. The Qinglong area underwent multiple deformation by NE–SW compression in the Middle-Late Jurassic times, WNW–ESE compression in the Late Jurassic to Early Cretaceous, ENE–WSW extension in the Early Cretaceous and NNW–SSE compression in the Late Cretaceous during the final stage of the Yanshanian orogeny. Meanwhile, widely distributed granite intrusions and emplacement of the Upper Jurassic-Lower Cretaceous volcanic rocks indicate a large amount of magma input into the area. The Qinglong area with the Great Wall along its southern margin close to adjacent plain to the south was uplifted to form the Qinglong highland and surrounding related basins by combination of the following three processes: the multiple tectonic Late Jurassic and Late Cretaceous shortening processes related to Yanshanian orogeny, Early Cretaceous regional extension triggered by slab-retreat of the Paleo-Pacific ocean and inflation of large amount magma at depth during Jurassic and Early Cretaceous.