Control of deep-water sedimentation on rift margin by non-coaxial fault linkage system: a case study from the steep slope of the Dongying Depression, Bohai Bay Basin, China

Understanding the evolution of the segmented synsedimentary fault linkage, which controls the accommodation development, sediment infill, and stratigraphic architecture, is essential for reconstructing rift histories and exploring natural resources. This study investigates the tectono-sedimentary processes in the steep slope of the Dongying Depression within the Bohai Bay Basin rift system, eastern China by utilizing three-dimensional seismic and drilling data. A classification scheme for non-coaxial extensional fault linkage styles is proposed, categorizing them into two types—partial linkage and through-going hard linkage—with eight subtypes based on geometric architectures, evolutionary stages, and segment-scale activity. Statistical analysis of the length and separation distance of the main border fault (the Chennan Fault) reveals that non-coaxial linkage systems are pervasive along the northern rift margin of the Dongying Depression. These systems controlled the development of its irregular zigzag geometry. Furthermore, analysis of non-coaxial convergent fault linkage processes provides the most plausible explanation for the initial morphology of the large paleo-gullies observed on the steep slope. Seismic-geomorphologic mapping and borehole dataset allow us to constrain the spatial and architectural variability of depositional systems along the rift margin. The results demonstrate that non-coaxial fault linkage processes control deep-water depositional types: basinal fans dominate during partial linkage phases, while nearshore subaqueous fans develop under through-going linkage conditions. Non-coaxial fault segment activity influences sediment input directions: uniform fault activity promotes longitudinal transport systems, whereas heterogeneous activity controls oblique delivery along dominant fault segments. This study enhances the understanding of non-coaxial fault systems and their sedimentary responses, providing a reliable basis for hydrocarbon exploration in the steep slopes of lacustrine rift basins. • A novel classification of non-coaxial fault linkage systems elucidates their control on deep-water sedimentation in rift margins. • Non-coaxial fault linkage stages dictate depositional system: partial linkage favors basinal fans, while through-going linkage promotes nearshore subaqueous fans. • Fault segment activity governs sediment dispersal pathways, with uniform slip enabling longitudinal transport and heterogeneous slip driving oblique delivery. • Integrated tectonic-sedimentary models enhance hydrocarbon exploration strategies in lacustrine rift basins by linking fault kinematics to sediment distribution.