Syn-Subduction Strike-Slip Faults Shape an Accretionary Orogen and its Provenance Signatures: Insights From Sikhote-Alin in NE Asia During the Late Jurassic to Early Cretaceous

Sedimentary rocks provide key information on source-to-sink systems and the regional expression of plate tectonics. The abruptly changing provenance signature of sedimentary rocks is commonly ascribed to changes in the source regions, such as continental collision events, the rise of mountain chains, reorganization of river systems and climatic change. However, moving the positions of the sinks (depocenters) geographically can also change the provenance record, but this is rarely considered. Typically, large-scale strike-slip faults can transport depocenters for long distances, thus altering the provenance information. In this study, we present a systematic investigation of the provenance changes in the Sikhote-Alin orogenic belt in the Russian Far East to evaluate this process. The Central Sikhote-Alin Fault is a margin-parallel strike-slip fault that developed along the NE Asian continental margin from the late Mesozoic. Our new detrital zircon U-Pb data, together with a compilation of geochronological data, indicate two different types of provenance signatures available: the sediments to the west of the fault were mainly derived from the adjacent Central Asian Orogenic Belt, but to the east of the fault, they were mainly supplied from the Korean Peninsula, which is several hundred kilometers away. It is proposed that these different sedimentary rocks were juxtaposed by syn- and post-subduction sinistral displacements along the fault, and were not related to local variations in the source regions. Thus, understanding the shifting positions of depocenters is important when decoding provenance change because lateral displacement is critical for reconstructing regional paleogeography along oblique convergent plate margins.