Two-stage rifting of Jiaolai Basin, Eastern China, decoding from the source-to-sink reconstruction

Abstract

<p>The basin is an essential window for exploring tectonic evolution, which preserves the information of regional extension, subsidence, uplift, and denudation. The Jiaolai Basin, located on the northern the Sulu Orogenic Belt, records the extension events of East Asia and the post-orogenic evolution of the Sulu Orogenic Belt during the Cretaceous. Multiple provenance analyses were used in the study to reconstruct the source-to-sink system of the Laiyang Group in the Jiaolai Basin. The results show that the Jiaolai Basin has a two-stage evolution history. In the early Early Cretaceous (ca. 135-122Ma), the Zhucheng sag and Gaomi sag in the south developed firstly. Subsequently, in the late Early Cretaceous (ca. 121-113Ma), the Laiyang Sag in the north developed. Moreover, these sags undergone independent, multi-stage source-sink system evolution in their early stages, and shared similar provenance supply systems at the end of Laiyang Group (ca. 113Ma). The provenance analysis results show that at ~121 Ma, ultra-high pressure (UHP) rock undergone a rapid exhumation in the northern section of the Sulu orogenic belt, whereas, for the southern section, The UHP may not be exposed until ca.113Ma. The two-stage extension in Eastern Asia with the change in direction and magnitude, recorded in the Jiaolai basin, suggests the trench retreat and subduction direction Change of the Izanagi plate should be the first-order drive force of the extension events of Eastern Asia during the Cretaceous. Our results indicate that the change of the Izanagi subduction direction may be ~121 Ma.</p>