Abstract: According to the field survey of geological phenomenon in Getang Gold deposit，the ore body of the deposit mainly occurs in the ancient karsts surface which is upon the Maokou formation，Section 1 of Longtan formation is the major ore-bearing layer.Both of ancient karsts side and the surface between the section three and four of Longtan formation are slip-sheet structure，the lithological combination of the second and third section of Longtan formation are clay stone with carbon and siltstone and this two sections are the intensified layer.The imbricate structure system is formed during the tectonic movement process between Indo-Chinese epoch and Yanshan epoch.During this period，the direction of regional pressure is changed from north-south to east-west，and the imbricate structure system is the result of multiphase tectonic movement.The fracture surface of imbricate thrust fault which is formed in the intensified layer is in a condition of maximum stress and closed extrusion，and this condition has disadvantage of the migration of ore-forming fluid.Additionally，poor water permeability of the rock plays a role of geochemical barrier to ore fluid，which provides the favorable conditions to the ore-forming of ore-bearing solution in the slip-sheet structure.Moreover，carbon exists in the intensified layer and becomes upward thinning.When the ore-bearing fluid flow through，the value of pH will be changed，the concentration of gold in fluid will be increased，and gold will be extracted from the clathrate and adsorbed by the carbon.Only relatively less mineral flow into the intensified layer，so just mineralization is found instead of ore body.

Key words: Tectonic deformation, Ancient karsts surface, Geochemical barrier