SOURCE-TO-SINK SYSTEM RECONSTRUCTION IN THE NORTHERN JIAOLAI BASIN, EASTERN CHINA BY MULTIPROXY PROVENANCE METHODS AND IMPLICATIONS FOR EXHUMATION OF THE SULU OROGEN

The Early Cretaceous sedimentary successions in the Jiaodong-Laiyang (Jiaolai) Basin, Eastern China provide valuable information about sediment provenances and tectonic processes. A clear understanding of the provenance of the Jiaolai Basin developing along the northern margin of the Sulu orogen and formed in the post-orogenic period elucidates the exhumation history of the Sulu orogen. However, the precise age and provenance evolution of the Early Cretaceous stratigraphy remain ambiguous. Here, we employ multiple sediment provenance proxies – detailed paleocurrents, conglomerate clast counts, detrital composition point counts of sandstone, and detrital zircon U-Pb geochronology – to reconstruct the source-to-sink system of the northern part of the Jiaolai Basin. Visual and statistical analyses of the different proxy results and comparison with the signatures of potential source regions reveal that (1) the lowermost Wawukuang Formation (Fm) (depositional age ca. 123 Ma) was mainly sourced from the Guocheng uplift (part of the Jiaobei terrane) in both the Haiyang and Laiyang regions of the Jiaolai Basin; (2) from the Linsishan to Zhifengzhuang Fm (ca. 121 Ma), the Laiyang region was mainly fed by sediments from the Jiaobei terrane, where widespread Cretaceous plutons were exposed at the surface, while for the Haiyang region, the Guocheng uplift and Sulu orogen were primary sources; (3) from the Shuinan to Longwangzhuang Fm, the Haiyang and Laiyang regions linked as a single basin fed by the Jiaobei terrane and Sulu orogen; and (4) the top Qugezhuang Fm (ca. 114 Ma) was sourced from Early Cretaceous plutons in the Sulu orogen and Jiaobei terrane. Based on the inflection point in the proportion of ultrahigh-pressure metamorphic (UHP) rock ages between the Wawukuang and Linsishan Fms, the unroofing time for the UHP rocks in the Sulu orogen occurred from 123-121 Ma, indicating initial rapid uplift of the Sulu orogen ca. 121 Ma. Also, our results show that the denudation processes of the Mesozoic plutons in the Sulu orogen have an obvious time sequence: Jurassic plutons first, followed by Cretaceous plutons.