Abstract
A pre-existing fault plays a quantitative role on the source-sink system of later tectonic stage. The activity of a source area is related to the reactivation of per-existing faults, including slope gradient, scale of paleo-valley, accommodation space, and depositional system in the sink. We studied the Paleogene succession on the southern gentle slope side of the Chengbei sag, Bohai Bay Basin based on well-log data and 3-D seismic data, from which three tectonic stages were identified, i.e., initial rifting stage (from the Kongdian Formation to the fourth member of the Shahejie Formation period), climax rifting stage (from the third member of the Shahejie Formation to the first member of the Shahejie Formation period), and post-rift thermal subsiding stage (in the Dongying Formation period). The reactivation of old faults significantly affected fault growth and activity manner in later rifting stages and controlled the sediment supply, providing space for different types of sedimentation and shape the form of gentle-slope source-sink system in the Chengbei sag. During the initial rift stage (66–42 Ma), small fault activity created low uplift of source area with a gentle slope, followed by small paleo-valleys with sediment filling. During the climax rifting stage (42–32 Ma), fault activity intensified, leading to a greater height and slope of the source area, forming large paleo-valleys with more sediment supply. During the post-rift thermal subsiding stage (32–23.3 Ma), fault activity decreased, and the height and size of the source area were reduced correspondingly with smaller slope, paleo-valley, and sediment supply.
Paper Information:
Jia, C., Li, W. & Wu, Z. How reactivated pre-existing normal faults influence the dynamics of source-sink system and sediment fill: a case study of eastern Chengbei sag. J. Ocean. Limnol. (2026). https://doi.org/10.1007/s00343-025-5023-2
