气候地层法在我国第四系分层中的运用问题-兼论第四纪气候干湿变化与冰期的关系

我国第四纪气候干湿交替的现象,虽曾为一些学者所注意,但由于我国第四纪地层开始形成时,现代东亚季风气候即已建立,气候干湿交替一般来说在地层中反映得不如冰期时受西风气旋带影响地区那样明显。所以,在很长一段时期内,未能采用以气候干湿变化为基础的气候地层方法。至1959年,刘东生先生在总结黄土地层划分经验之后,才明确提出采用雨期和间雨期划分北方第四系的意见。

ON THE APPLICATION OF THE PALEOCLIMATIC STRATIGRAPHY TO THE QUATERNARY STRATIGRAPHICAL DIVISION IN CHINA

During the ice age, the dropping of .temperature on a global scale caused changes in rainfall ( both in direction and in quantity ) in various nonglacial regions because of their different geographical environments. In the eastern part of Asia, the full development of glaciers, particularly that of the permafrost, led to the strengthening .of the continental climate, the southward movement of high-latitude .Zonal system, and the strengthening of the power and lengthening of the duration of the Siberia high atmospheric pressure, all of which, as a result, enhanced the influence of the arid-cold winter monsoons, and caused the decrease of rainflal in most regions of China, and, even of East Asia. But during in the interglaction, most of the abovementioned regions were humid-hot or humid-temperate because of the strengthening effect of summer monsoons. Not all the so-called "pluvial" phenomena in the past in the interior regions of west China were caused by the increase in rainfall in most cases. Each of those phenomena of different ages and regions should be analyzed and studied separately.