Sedimentary Setting and Ore-Forming Model in the Songtao Manganese Deposit, Southwestern China: Evidence from Audio-Frequency Magnetotelluric and Gravity Data

The break-up of the supercontinent Rodinia in late Neoproterozoic led to formation Nanhua rift basin within South China Block. Datangpo-type manganese deposit, which developed basin, is one most important types deposits China. Although it widely accepted that deep sedimentary structures significantly affect ore system, relationship between and rifting process still unclear. origin layer remains controversial. In this paper, we integrated audio-frequency magnetotelluric (AMT) data, gravity comprehensive geological borehole data analysis characterize structure deposit Songtao, Guizhou Province. resistivity density models produced an inclined layered structure, correlated well with coeval sediment strata basin. A high-resistivity cap was observed from surface a depth 800 m, corresponding Cambrian Loushanguan (ϵ3−4ls) Palang dolomite (ϵ2p), has helped storage ore. significant low-resistivity anomaly (25–40 Ω·m) resides at 1400 m Nantuo (Nh3n) gravel sandstone Datangpo (Nh2d) silty carbonaceous shale, ore-forming layer. This distinct possibly by aqueous fluids pyrite syn-sedimentary fault alteration zone. accumulations sulfide minerals rock samples suggest possible anoxic-euxinic deposition environment during mineralization precipitation. revealed perhaps previous zone extension process, provided migration upwelling channels for minerals. Based on our models, survey, model derived, can help provide geophysical evidence deposit.