The controlling factors of major metallogenic systems in south china based on gravity and magnetic analysis

Metallic deposits such as W-Sn, Cu-Au, rare earth deposits, thus serving as a “giant granary” of metal mineral resources in China(Lü  et al.,2021). There are five large-scale metallogenic belts only in the east of South China, namely the Middle-Lower Yangtze River Metallogenic Belt (MLYMB), Qingzhou-Hangzhou Metallogenic Belt (QHMB), Nanling Metallogenic Belt (NLMB), Wuyishan Metallogenic Belt (WYSMB), and Xiangxi-E’xi Metallogenic Belt (XEMB).

The source zones of the mineral systems in major metallogenic belts in South China are reflected by the vertical structures of the lithosphere in this area. In MLYMB, the mineral systems of the Fe and Cu deposits have multi-level source zones. The initial-level source zone is the enriched mantle, which is formed owing to the thinning of the lithosphere and deformation caused by the fluids in the asthenosphere. In QHMB, the source zone of Cu deposits such as the Dexing deposit is the mantle, while the source zone of W deposits on the margin of the Moho uplift such as Zhuxi and Dahutang deposits is the remelted crust. As for QHMB, the W and Sn mineral systems originate from the crustal magma. In WYSMB, the diagenism and mineralization are mainly related to the interactions between materials in the crust and the mantle. The crust-derived materials form the deposits mainly containing W and rare earths, and mantle-derived materials form polymetallic deposits such as Cu and Au. As for XEMB, it consists mostly of metal deposits of the type of strata-bound sedimentation with the crust as the source zone, such as Sb, Pb, Zn, and Mn deposits.

The pathways of the mineral systems of the major metallogenic belts in South China are deep faults and block or terrane boundaries determined by edge detection of gravity anomalies, as well as density contrast boundaries obtained with the 3D density model. The metallogenic pathways of Fe and Cu deposits in MLYMB mainly include the Yangtze River deep fault in NE trending and Tongling-Taizhou fault in SE trending and its secondary faults. The eastern segment of QHMB is mainly controlled by the faults in northeast Jiangxi, the southern segment of QHMB and the NLMB are mainly under the control of the boundary faults of F1, and WYSMB is related to Zhenghe-Dapu fault and Heyuan-Shaowu fault.

 A 3D density and susceptibility model was obtained by 3D gravity and magnetic inversion. The distribution of different types of deposits was qualitatively reflected by different combination of density and susceptibility model, revealing the distribution of termination sites of different mineral systems in South China.Mineral systems in this area, providing indications for future ore-prospecting exploration in South China.