中国科学院地球环境研究所机构知识库

The pedostratigraphy and magnetostratigraphy of several sections in the Loess Plateau of north-central China have been investigated and correlated. The most complete and distinct loess-paleosol sequence occurs in the Baoji section of the southern part of the Plateau. Thirty seven pedostratigraphic units are identifiable in the Baoji section and correlated with those in other parts of the Plateau. The sequence represents thirty seven major cold to warm climatic cycles in the last 2.5 Myr. At about the time of the Matuyama-Gauss magnetic reversal an abrupt climatic event occurred iii north China, represented by the shift of the well weathered Red Clay formation below the M/G boundary to the alternating loess and paleosol units above, marking the beginning of a new epoch in the course of climatic evolution. In addition there are two other major shifts of dominant periods of climatic cycles recorded in the loess-paleosol sequences, one occurring at about 1.5 Myr and another at about 0.8 Myr. The pedostratigraphy of loess deposits in north-central China provides an independent measure of the world-wide climatic fluctuations and is now the most complete and reliable record of the major climatic cycles in the last 2.5 Myr.