关键词: 元谋断裂带, 砂脉, 断裂活动, 砂土液化, 伴生产物

Abstract:

The sand veins in Yuanmou fault zone have been investigated in the work, and its tectonic implications has been defined. The result shows that the sand veins generally develop in the surface or sub-surface rock straum in the middle-north segment of Yuanmou fault, and extends parallelly along the fault with larger dip angles. In addition, the patterns and structures of the sand veins and its relationship of the host rocks show that the sand veins were filled with the stretchable fracture from the overlying strata as the result of the sand liquefaction from the main fault plane or secondary fault pane which were connected with Yuanmou fault was intensively active, or due to the strong earthquake. Moreover, the thermoluminescence (TL) and optically stimulated luminescence (OSL) dating show that the sand veins were formed about 7 kaBP, indicating a intensive activity of Yuanmou fault during the Late Quaternary.

Key words: Yuanmou fault, sand vein, fault activity, sand liquefaction, accessory