摘要
Two lacustrine sporopollen records obtained from the Qaidam Basin (in the non-monsoonal region) and the Linxia Basin (in the monsoonal transition zone) indicate that during the early Pleistocene open forest-steppe/steppe vegetation developed in the Qaidam Basin, while in the Linxia Basin an open cypress forest-steppe shifted to a conifer/conifer-steppe and then to open forest-steppe vegetation. Existing sporopollen records from the Chinese Loess Plateau (CLP) (in the monsoonal region) indicate that around the Sanmen Paleolake open forest-steppe shifted to pine/conifer-broadleaved mixed forest. The conifer cover then changed to a subtropical evergreen broadleaved forest distributed around the Nihewan Paleolake. These changes suggest that wetter conditions progressed from western China to the east, and the climate became more humid than that of today indicating a stronger Asian summer monsoon during the early Pleistocene.
Two lacustrine sporopollen records obtained from the Qaidam Basin (in the non-monsoonal region) and the Linxia Basin (in the monsoonal transition zone) indicate that during the early Pleistocene open forest-steppe/steppe vegetation developed in the Qaidam Basin, while in the Linxia Basin an open cypress forest-steppe shifted to a conifer/conifer-steppe and then to open forest-steppe vegetation. Existing sporopollen records from the Chinese Loess Plateau (CLP) (in the monsoonal region) indicate that around the Sanmen Paleolake open forest-steppe shifted to pine/conifer-broadleaved mixed forest. The conifer cover then changed to a subtropical evergreen broadleaved forest distributed around the Nihewan Paleolake. These changes suggest that wetter conditions progressed from western China to the east, and the climate became more humid than that of today indicating a stronger Asian summer monsoon during the early Pleistocene.
基金
supported by the President Fund and Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-Q09-04)
the National Natural Science Foundation of China (40871098,40920114001 and 40802041)
the National Basic Research Program of China (2005CB422000)