Variation of terrestrial ecosystem recorded by stable carbon isotopes of fossils in northern China during the Quaternary

Stable carbon isotopes Of C-3 and C-4 plants have completely distinct delta(13)C values respectively. Carbonate in tooth enamel of herbivorous mammals is significantly and regularly enriched in C-13 compared to source carbon. As a result, we can reconstruct distributions Of C-3 and C-4 plants in geological history based on carbon isotopes of mammalian tooth enamel. Carbon isotopes of 70 mammalian tooth enamel samples from 11 Quaternary localities in northern China are analyzed. This analysis indicates that C-3 plants were dominant in the terrestrial ecosystem of northern China during the Quaternary, which is completely different from Pakistan with relatively close latitudes where C-4 plants were absolutely dominant. The great difference was caused by the uplift of the Tibetan Plateau. A simulation implied that a marked temperature decrease would happen in the north side of the Tibetan Plateau, but a temperature increase in the south side. The warming condition caused the transition from C-3 to C-4 plants in Pakistan situated in the south side of this plateau. In the north side, on the contrary, the cooling condition restrained the distribution Of C-4 plants. As a result, C-3 plants have been dominant in northern China until now.