Abstract: Northeastern Yunnan, located in the southwestern part of the Yangtze Block, developed a series of tectonic domes hosting low temperature or closely related deposits. Research on the structural origin and properties of these tectonic domes is beneficial for revealing the regularity of regional low temperature ore formation. The Jiache Dome in northeast Yunnan situates near Awang and Jiache towns. Compared with other domes in the area, the Jiache Dome developed a complete structurerock assemblage, typical of the regional tectonic domes. Focusing on the structural features of the Jiache Dome, the structural origin and deformation sequences of tectonic domes, characteristics of background anomaly of low temperature metallogenic elements, and occurrence of Pb, Zn, Ag, As, Sb elements were determined in this work, through detailed geological investigation, structural analysis, key stratum sample collection, geochemical and EMPA analyses, in combination with regional background data. By completing three crosscutting structural profiles of the Jiache Dome, it is discovered that the dome has experienced at least three stages of structural deformation (D1, D2, D3): D1 period developed consequent flow layer deformation, possibly of the Caledonian age; D2 period formed the NEE trending buckling fold with a supposed deformation age of the Indosinian; D3 period resulted in the NNE trending buckling fold, whose deformation age is postulated to be the Yanshanian. Results of geochemical analyses show that lowgrade metamorphic rocks in the Kunyang Group (for example muddy and silty slate) have background anomaly values 3 to 5 times higher than background levels for Pb, Zn, Ag, Sb, As and siltstone in the Chengjiang Formation of Sinian. Similarly, dolomite and black shale in the Dengying Formation exhibit background anomaly levels 3 to 5 times higher than background values for Pb, Ag, and As. And part of black shales in the Yuhucun Formation of the lower Cambrian show background anomaly values 5 times higher than background values for Pb, Zn, Ag, Sb, As. EMPA analysis suggests that these low temperature oreforming elements are mainly hosted in the primary pyrite. Results of structure analyses further show that the main body of the dome formed over the superposed NNE and NEEtrending folds, and it has experienced multistage tectonic superposition and transformation.

Key words: Jiache Dome, structural deformation sequence, structural style, superposed fold, element enrichment