Abstract: Based on the study of the relationship between the basic characteristics and gold mineralization at Hongtugou-Chuancigou in northern Qilian area, it is found that the gold mineralization in the area is controlled by the structural-altered rocks formed under ductile-brittle shearing in the ductile shear zones. The ductile shear zone served as ore-controlling and ore-hosting structures, and also severed as a channel for deep fluid transportation, provided a better condition for the movement and enrichment of the hydrothermal liquids and resulted in the formation of bonanza in the deposit. Supercritical fluids at the middle to lower crust levels could dissolve considerable amount of gold and other ore-forming elements in the form of sulfur complexes, and migrate upwards to shallow crust levels along some ductile shear zones. The rapid decrease of gold solubility in the fluid at shallow crust level led to precipitation of gold and formation of large gold deposit. The gold deposit at Hongtugou-Chuancigou in the northern Qilian area occurs in an Early Paleozoic collision orogenic belt, is a typical ductile shear zone gold deposit.The gold ore types are mainly cataclastic and altered rock type.

Key words: Hongtugou-Chuancigou, gold deposit, ductile shear zone, structural altered rock, Paleozoic orogenic belt