1. Department of Geology, Northwest University, Xi'an 710069, China;
2. State Key Laboratory of Continental Dynamics, Xi'an 710069, China

The earliest Besshi-type VMS deposits formed in Paleoproterozoic, and then widely occurred in Phanerozoic oceanic trench or fore-arc basin. The minerogenetic region has thick sedimentary rock formation underlain by the volcanic rocks, which is significant for ore-forming material exchanging and metal elements enriching. The strong beresitization occurred in the footwall of Besshi-type deposits while weak chloritization and carbonation occurred in hanging wall. The deposits consists of single orebody or 2~3 connected orebodies. In profile, from bottom to top it comprises pillow basalts, massive pyrite ore with coper, blocky banded flint pyrite ore, blocky jasper. The volcanic host rocks of Besshi-type VMS deposits are mostly calc-alkaline with a small number of tholeiitic series, and the geochemical characteristics of trace and rare earth elements are similar to the island arc volcanic rocks on the edge of the active continent. The sulfur in metallogenic fluid is from the mixed source of mantle and seawater, and the metallogenic elements are from mixed source of mantle-crust.