22/02/2021 · The Dachang Snpolymetallic ore district in South China is the second largest tin district in the world with a tin reserve of over one million tonnes. ZnCu skarn and stratiform, massive, and vein SnPbZn ores are all present in this district. This has led to a debate as to whether the Sn orebodies were formed by Cretaceous magmatichydrothermal replacement or Devonian submarine exhalative ...