Devonian basin evolution and mineralization in Nandan-Hechi area, Guangxi

Abstract：The Nandan-Hechi basin in Guangxi started rifting at the late Early Devonian Emsian stage, and withered and died out gradually with the closure of the paleo-Tethys ocean along the Jinsha River, Honghe River and Majiang River in Triassic. Geological field survey has revealed that crustal movement controlled the formation and evolution of the sedimentary basin, that the basement fault controlled the paleogeographic evolution, and that both of the two factors controlled the lithostratigraphic framework and provided ideal space at the late ore-forming stage. Event deposition was closely related to mineralization and all the ore-bearing layers were formed at the peak of event deposition. The second-order NW-trending rift-trough in the basin seems to be an important ore-forming location for large and superlarge tin-polymetallic deposits. Important mineralization resulted from submarine volcanic exhalation or eruption controlled by the second-order basement fault in the basin.