| Abstract: | This study area is located in the western North Tibetan Plateau, lying between the western Kunlun Mountains to the north and the Gangdise Mountains to the south, and covers an area of about 230000km\+2. Granitoid rocks occur widely in the area and mainly consist of huge intermediate\|acid intrusive rock\|bodies, which locally are accompanied by ultrabasic to basic rocks.Eight granite bodies from the locations were chosen for this study. Determinations of U\|Pb age on zircon and Rb\|Sr age on whole rock or mineral of these rock units were made using a Finnigan MAT\|261 mass spectrometer fitted with multi\|collector. The total procedural Pb,Sr blank were always in the 2～4 ng range and insignificant in comparison to the sample(milligram range). K\|Ar data were previously published and are reported again here in order to compare them with the Pb and Sr results. The results for the eight granite bodies reveal a complex age pattern. This area may be divided on the basis of these radiometric dates into 5 rock zones. These zones defined are, from north to south, the southern Kunlun, the Qiangtang, the Anglonggangri, the Gangdise and the Himalaya rock zones. |
