中国第四纪冰期、地文期和黄土记录

中国第四纪冰川的发育受岩石圈运动造成的三大地貌阶梯的严格控制,主要出现在最高阶梯的青藏高原和西北山地,第二阶梯以下分布零星。把冰期、地文期和黄土记录结合起来研究会迅速提高中国第四纪冰川的研究水平。兰州附近有三次古冰川遗迹,分别可以和T₁、T₂、T₃和T₄相应。相当于氧同位素2、4、6和16阶段,即70,000—10,000aB.P.、0.15MaB.P.和0.6MaB.P.。

QUATERNARY GLACIATIONS, PHYSIOGRAPHIC STAGES AND LOESS RECORD IN CHINA

The development of Quaternary glaciers in China was closely controlled by three geomorphic steps formed by the lithosphere movements during long-term geological time, and the glaciers were mostly distributed on the highest step—the Qinghai-Xizang（Tibet） Plateau and mountain ranges in the Northwest China, and only few Quaternary glacial traces reached below the second step. But the influences of glacial-interglacial climatic fluctuations were common in China. They were reflected by Quaternary environment coordinating changes, such as Quaternary glacial advances and retreats, loess and paleosol cycles, the moving of animals and the successions of vegetations, and sea level changes. The studies of glaciation and interglacial, division of physiographic stages and loess stratigraphy are some important aspects of Quaternary research in China. Recently, studies on Quaternary glacial traces, the Huanghe （Yellow） River terraces and the loess-paleosol sequence near Lanzhou have been carried out, compared with oxygen isotope curve in deep-sea sediments, it was found that the terms of the three Quaternary glaciations near Lanzhou could correspond to the formation periods of gravel beds at Huanghe River terraces: T₁, T₂, T₃, and T₄ and correlate to L₁, L₂, and L₆ of Chinese loess records, and stages of 2,4, 6, and 16 of oxygen isotopes in the deep-sea sediments. Their ages are 70,000—10,000 aB. P., 0.15MaB. P. and 0.6MaB.P. respectively. The interglacial periods （or interstadial stages） corresponded to the paleosol formational periods in the loess-paleosol sequence, and terrace down-cutting periods.