Abstract:

The Fulechang Zn-Pb deposit is one of the typical deposits at the southeastern region in the deposit concentration district of Northeastern Yunnan. In this paper, the geological characteristics for faults of different trends and phases and their relations to mineralization have been systematically elucidated based on large-scale mapping and the dynamics theory and method of tectonic ore-forming processes. Typical faults are selected for identification of the mechanical nature of fault planes and for division into tectonic episodes and tectonic systems. The area experienced EW-trending compressive stress from the Jinning period to the Chengjiang period, NW-SE-trending extrusion from the Indosinian period to the early Yanshanian and NE-SW-trending tectonic process from the mid-late Yanshanian to the Himalayan period. At first, the primary stress process from the Indosinian to the early Yanshanian provided a favorable metallogenic geological background; and NE-trending compressional-shear faults and NW-trending tensional faults twist made metallogenic fluid filling, enrichment and mineralization; then EW-trending shear faults are ore-breaking structure. Based on the relationship between structure and mineralization, the research provides important evidences for forecasting concealed deposits or ore-bodies.

Key words: fault structure, tectonic mineralization, Fulechang Zn-Pb deposit, deposit concentration district of Northeastern Yunnan Province