Single_zircon evaporation method was employed in the present study to determine the age of the iron_bearing rock series in Precambrian strata in the western sector of the northern Qilian Mountains. Three zircon ages f...Single_zircon evaporation method was employed in the present study to determine the age of the iron_bearing rock series in Precambrian strata in the western sector of the northern Qilian Mountains. Three zircon ages from the diabase of the Aoyougou ophiolite previously put into Upper Lithologic Formation of the Zhulongguan Group are (1 840±2), (1 783±2) and (1 784±2) Ma respectively, whereas the zircon ages from the welded breccias in the Zhulongguan Group are (733±7), (738±4) and (604±6) Ma respectively. These results show that they should belong to the bottom of the middle Proterozoic and the upper part of upper Proterozoic respectively.展开更多
文摘Single_zircon evaporation method was employed in the present study to determine the age of the iron_bearing rock series in Precambrian strata in the western sector of the northern Qilian Mountains. Three zircon ages from the diabase of the Aoyougou ophiolite previously put into Upper Lithologic Formation of the Zhulongguan Group are (1 840±2), (1 783±2) and (1 784±2) Ma respectively, whereas the zircon ages from the welded breccias in the Zhulongguan Group are (733±7), (738±4) and (604±6) Ma respectively. These results show that they should belong to the bottom of the middle Proterozoic and the upper part of upper Proterozoic respectively.
