Source-to-sink system reconstruction in the northern Jiaolai Basin, eastern China, by multiproxy provenance methods and implications for exhumation of the Sulu orogen

Abstract

The Early Cretaceous sedimentary successions in the Jiaodong-Laiyang (Jiaolai) Basin provide valuable information about sediment provenances and tectonic processes. A clear understanding of the provenance development of the Jiaolai Basin along the northern margin of the Sulu orogen and would elucidate the exhumation history of the Sulu orogen during the post-orogenic period. However, the precise age and provenance evolution of the stratigraphy remain ambiguous. Here, we employ multiple provenance proxies – detailed paleocurrent, 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) Wawukuang Formation (Fm) (ca. 123 Ma) was mainly sourced from the Guocheng uplift in both the Haiyang and Laiyang regions; (2) Linsishan to Zhifengzhuang Fm (ca. 121 Ma), the Laiyang region was mainly fed by the Jiaobei terrane, while in the Haiyang region, the Guocheng uplift and Sulu orogen were primary sources; (3) Shuinan to Longwangzhuang Fm, the Haiyang and Laiyang regions were linked as a single basin fed by the Jiaobei terrane and Sulu orogen; and (4) Qugezhuang Fm (ca. 114 Ma) was mainly sourced from Early Cretaceous plutons in the Sulu orogen and Jiaobei terrane. Based on the inflection point in the proportion of ages of the ultrahigh-pressure metamorphic (UHP) rocks between the Wawukuang and Linsishan Fms, we conclude that the Sulu belt experienced a rapid uplift that resulted in the exposure and erosion of the Jurassic plutons and UHP rocks during ca. 123–121 Ma. In addition, our results show that the denudation processes of the Mesozoic plutons in the Sulu orogen have an obvious temporal sequence: Jurassic plutons first, followed by Cretaceous plutons.