Mapping of geological complexity and analyzing its relationship with the distribution of gold deposits in the Guangxi Gold Ore Province, Southern China

The Guangxi gold ore province contains >370 gold deposits with total resources of >260 t Au. Factor analysis (FA) of geochemical data, and calculation of lineament density within 10 km, 20 km, and 30 km circular search grids across a geological map, were applied in Guangxi to highlight geological complexity and to analyze its relationships with the distribution of gold deposits. The FA of stream sediment geochemical data for 42 elements, subjected first to center logarithmic transformation (clr), yield several element combinations that allowed distinction of metallogenic signatures from geological backgrounds. The element combinations of the first and second factors were Cd–Co–Cr–Cu–Li–Mn–Ni–P–Sb–Y–Zn–Mg and Be–Bi–La–Nb–Pb–Sn–Th–U–W–Zr–Al, and the spatial distributions of their factor scores overlap the Devonian to Permian strata and granite, respectively. The distribution of factor scores of mineralization-related element combination, Ag–As–Au–Mo, coincides with 70 % of gold deposits. The lineament density mapping can highlight different-scale faults and lithological contacts by using circular search grids with different diameters. The C–A fractal modeling for lineament density has indicated four populations, namely low, moderate-low, moderate-high, and high lineament densities. About ∼80 to ∼90 % of the known gold deposits exist in areas with moderate-low to moderate-high lineament densities. This highlights the importance of distinguishing geological complexity based on faults and lithological contacts, which are commonly the pathways for the focused fluid flow and gold ore formation. The deposit-scale geological complexity mapping has predicted several exploration targets, where high-grade gold orebodies have been prospected successfully by drilling in 2018. The geological complexity mapping is a kind of geochemical and geological complementation for resource potential assessment.