Delamination occurs mainly in the lithospheric mantle, involving interaction with the asthenosphere, the process of which is hard to observe directly. Our research on granitoids in the western Kunlun orogenic belt, China, indicates that high contents of the heat|producing elements Th and U may furnish lithospheric delamination with new evidence. At the same time, we have established the Th|SiO-2 and U|SiO-2 diagrams to discriminate delamination. Delamination occurs mainly in the lithospheric mantle, involving interaction with the asthenosphere, the process of which is hard to observe directly. Our research on granitoids in the western Kunlun orogenic belt, China, indicates that high content of the heat | producing elements Th and U may furnish lithospheric delamination with new evidence. At the same time, we have established the Th | SiO - 2 and U | SiO - 2 diagrams to discriminate delamination.