Research On The Yangshui Anticline In Central GuiZhou Uplift And The Background Characteristics Of Its Low Temperature Ore-forming Elements As,Sb,Au And Ag

This paper focuses on the structural characteristics of the Yangshui Anticline in the central Guizhou Uplift and its relation to regional low-temperature metallogenic material basis(LTMMB).The structural styles,deformation sequences,stages and formation of the Yangshui Anticline are identified and discussed based on previous results and our detailed geological survey.The large-scale LTMMB are established by whole-rock geochemical analysis and electron probe microanalysis on pyrite.Relationship between Yangshui Anticline and the LTMMB are then discussed based on abundance anomalies of the low temperature ore-forming elements,such as Sb,As,Ag and Au within the Yangshui Anticline.The main results of this paper are as follows:1)The Yangshui Anticline is characterized by cross-over anticline with at least three identified deformations,D1,D2 and D3.The D1 is EW-trending buckling fold.The D2 is NS-trending buckling fold.The D3 is later extruded reform.The results of structural analysis show that the formation of Yangshui Anticline experienced from the Caledonian EW-trending fold(D1)to Indosinian NS-trending fold(D2)and then finalizing the design on the condition of extrusion(D3)in Yanshan tectonic event.2)Geochemical analysis show that the average content of Sb,As,and Ag in Banxi Group and Sb,As,Ag,and Au in Sinian System are all higher than the average abundance values of upper crust in Yangtze Block.However,the average content of Au in Banxi Group is lower than the average abundance value of upper crust in Yangtze Block.Besides,the high abundance values are mainly found in the tuff of the Banxi Group and phosphorite of Yangshui Formation in Sinian System.The results of electron probe microanalysis of pyrites suggested that low temperature ore-forming elements Sb,Au and As mainly exist in primary pyrite and other minerals.3)Based on characteristics of low temperature ore-forming elements in the study area,structural analysis for Yangshui Anticline and the regional geological evolution,I suggest that multistage deformations of Yangshui Anticline activated and enriched the low temperature ore-forming elements,such as Au,As and Sb.Above results have theoretical and practical significance for understanding the formation and the evolution of the Central Guizhou Uplift and its contribution to the large-scale LTMMB in region.