Mesozoic is a critical period for the formation and development of sedimentary basins in East China. The unconformity structure is a response of the Mesozoic deformations. To delineate the paleotectonic framework and evolution of the basin, we carried out a systematic investigation of the contact horizon, structural style and spatial distribution of the Mesozoic unconformities in the Huanghua Depression. The results showed that three sets of secondary unconformities developed in the Huanghua Depression during Mesozoic. The unconformities of the Jurassic-Pre-Jurassic and Cretaceous-Pre- Cretaceous are mainly parallel and monoclinic unconformities respectively. Fold unconformity and fault-fold unconformity are common in tectonic accommodation zones. The unconformities of Paleogene-Pre-Paleogene in the uplift structural belt are commonly monoclinic, fault fold and fold unconformities, while those in the depression area are commonly parallel unconformities. The paleostructure was likely a gentle fold structure in the Late Triassic. The northern part of the basin was denudation area, whereas the southern part was continental subsidence area in the Late Jurassic. However, the northern part turned into continental subsidence area while the southern part of the basin a denudation area in the Late Cretaceous. The Mesozoic tectonic evolution can be divided into three stages of subsidence and three stages of uplift. The depression basin experienced the Early Triassic subsidence, the Middle-Late Triassic uplift and denudation, the Early-Middle Jurassic differential subsidence, the Late Jurassic compression-torsion uplift and denudation, the Early Cretaceous differential subsidence, and the Late Cretaceous regional uplift and denudation. The tectonic accommodation zone was the key boundary of basinal subsidence and uplift. The unconformity structure recorded the intensity of tectonic activity, paleotectonic pattern, and development of the sedimentary basin. © 2020, Science Press. All right reserved.
