Introduction The widespread occurrence of Cenozoic magma of the Tibetan Plateau suggest that they are common to most destructive plate margins and orogenic belts and active faults. In northern Tibet, volcanic rocks ar...Introduction The widespread occurrence of Cenozoic magma of the Tibetan Plateau suggest that they are common to most destructive plate margins and orogenic belts and active faults. In northern Tibet, volcanic rocks are divided into two volcanics subzone, i.e., the Qiangtang subzone and Kunlun subzone.We found most shoshonitic lavas in Kunlun subzone had extruded for 0～17Ma..The sodic volcanics had erupted for 44～60Ma in western Qiangtang subzone and the most potassic lavas had extruded for 18～45Ma, in eastern Qiangtang subzone.The volcanism in Qiangtang starting 60Ma ago, most volcanic rocks dominantly formed between 45 and 18Ma (Fig.1). From 45Ma to 18Ma, there is a trend that the strength of volcanism gradually decreases. The peralkaline volcanism occurred in late Palaeogene and was re\|active at local area in Neogene.展开更多
文摘Introduction The widespread occurrence of Cenozoic magma of the Tibetan Plateau suggest that they are common to most destructive plate margins and orogenic belts and active faults. In northern Tibet, volcanic rocks are divided into two volcanics subzone, i.e., the Qiangtang subzone and Kunlun subzone.We found most shoshonitic lavas in Kunlun subzone had extruded for 0～17Ma..The sodic volcanics had erupted for 44～60Ma in western Qiangtang subzone and the most potassic lavas had extruded for 18～45Ma, in eastern Qiangtang subzone.The volcanism in Qiangtang starting 60Ma ago, most volcanic rocks dominantly formed between 45 and 18Ma (Fig.1). From 45Ma to 18Ma, there is a trend that the strength of volcanism gradually decreases. The peralkaline volcanism occurred in late Palaeogene and was re\|active at local area in Neogene.
