Abstract:
Using aeromagnetic and aerogravity data from Shanghai and its adjacent areas, the three-dimensional inversion is employed to construct crustal density contrast and the magnetic magnetization models for the study area. To analyze the crustal structural characteristics, the corresponding analysis of gravity and magnetic anomalies revealed that the sources of these anomalies are unrelated but exhibit accompanying features. Medium-to-strong magnetism is widely distributed along density anomaly gradient zones, suggesting that intrusive medium-to-acidic granites along the margins of uplifted structures are the primary factors causing the magnetic anomalies. Based on the density and magnetic models, a crustal ring structure in the Yangtze Estuary is identified, and the tectonic characteristics of the Hu-Su and Jiang-Shao faults are analyzed in detail. The gravity and magnetic features of the Jiang-Shao fault segment entering the East China Sea are examined, indicating that these two faults extend to a depth of 20 km, controlling the tectonic framework of the Shanghai region.