Where is Qinzhou-Hangzhou juncture belt? Evidence from integrated geophysical exploration

The suture zone between the Yangtze Paleoplate and the Cathaysia Paleoplate (called Qin-Hang junction belt) is one of the most important tectonic-magmatic-metallogenic belts in southeastern China. There is still considerable controversy over the method of dividing the location and boundary of the western section of the Qin-Hang junction belt. In order to identify and determine the boundaries of the Qin-Hang junction belt, the authors employed the large-scale satellite gravity and magnetic data in combination with the integrated processing and analysis of regional magnetotelluric and broadband seismic data. The comprehensive evaluation shows that the Qin-Hang junction belt is the southern boundary of the Jiangnan orogenic belt. The authors hold that the border is Ningbo-Jinhua-Shangrao-Ganzhou-Chenzhou-Beihai in the south and Shanghai-Huzhou-Yingtan-LinchuanPingxiang-Hengyang-Yongzhou-Guilin-Wuzhou-Qinzhou in the north. On both sides of the joint belt, both the gravity field and the magnetic field have distinct characteristics, indicating the different material compositions and basements between the Yangtze and Cathaysia plates. There are also local differences in the geophysical fields of the Qin-Hang junction belt, suggesting that the tectonic belt has undergone multiple stage magmatism and formed different combinations of metal deposits in different sections, forming a unique metallogenic belt, i.e., the Qin-Hang metallogenic belt.