GEOLOGIC FEATURES AND MULTIPERIODIC SYNTOPOGENIC METALLOGENESIS OF THE LAOCHANG CU-POLYMETAL DEPOSIT IN LANCANG,YUNNAN

In Lancang region,the crust underwent the opening and closing development evolution in different degrees during Paleo-, Meso-and Neo-Tethys,which resulted in the special geological features of Laochang Cu-polymetal deposit in Lancang. Under the control of multiperiodic syntopogenic tectonism, the volcano-exhalative deposition massive sulphide Ag-Pb-Zn ore bodies were formed in Paleo-Tethys, the vein ore bodies formed In the Meso-Tethys tectonic hydrothermal activity and the sharn Cu ore bodies and deep-seated Sn mineralism formed associated with the granite intrusion in Neo-Tethys. The features of multiperiodic syntopogenic superimposed metallogenesis are very distinct.