Multi-element geochemical data mining: Implications for block boundaries and deposits distributions in South China

Abstract To explore the macroscopic characteristics of geological block boundaries, Mesozoic magmatic rocks, and various ore deposit distributions in South China, we processed large-scale stream sediment geochemical data that covered the entire South China region. Two unsupervised data mining algorithms, including cluster analysis and correlation analysis, were used to identify the geochemical distribution patterns. The combined geochemical pattern of nine major elements showed two gradient lines that divide the South China region into three blocks. These gradient lines reveal the eastern and western boundaries of the intracontinental orogenic belts between the Yangtze and the Cathaysia blocks. We suggest that the Nanning-Pingxiang segment is located on the southern end of the Yangtze-Cathaysia block boundary, and the Jishou-Kaili segment is a part of the boundary between the Yangtze block and the eastern orogenic belt. In the Mesozoic, the distribution of magmatic rocks migrated from inland to the southeast coast. Meanwhile, the mantle-derived compatible elements gradually deplete, whereas the crust-derived incompatible elements gradually become enriched. The migration and enrichment of geochemical elements provides material sources for the formation of various ore deposits. High-temperature metallogenic deposits related to Mesozoic magmatic activity are widely developed in eastern South China, while low-temperature metallogenic, sedimentary, and metamorphic deposits are more developed in inland South China. The regional geochemical patterns can indicate the distribution of deposits to varying degrees.