Early Jurassic initiation of the modern drainage pattern of the Dabie orogen (East China) revealed by a multi-proxy provenance approach

Abstract

The timing of the initiation of the present-day tectonic architecture and drainage systems in eastern China remains debated. This study presents a comprehensive provenance study of the Early Jurassic peripheral basins surrounding the Dabie orogen including framework petrography, heavy-mineral analysis, single-grain chronology and chemistry. Clasts of high-grade schist, muscovite grains, rare gneissic fragments, abundant metamorphic garnet and phengite (Si > 3.3 pfu), combined with a main 216–256 Ma rutile U–Pb population found in these Early Jurassic sandstones, indicate a source from the Triassic (U)HP belt in the Dabie orogen. Sedimentary lithics and ultra-stable heavy-mineral assemblages indicate an additional source of recycled sedimentary rocks. Combined with the continuous shift of the youngest detrital rutile age population toward younger ages toward the north that mimics the pattern of metamorphic bedrock ages in the Dabie orogen, we infer that the present surface tectonic architecture and paleodrainage patterns of the Dabie orogen were established in the Early Jurassic. Thus, the Early Jurassic exhumation of the Dabie orogen marked the development of the watershed between Northern and Southern China, namely the Huai River and several principal tributary systems of the middle-lower Yangtze River.