关于南国冰臼群成因的商榷之二

A DISCUSSION ON THE ORIGIN OF MOULINS IN SOUTH CHINA(2)

南国冰臼群分布区大量冰川堆积、冰川条痕石及变形砾石的发现 ,再次有力地证明是“冰臼”不是“壶穴”的正确结论。由冰川漂砾经融冻作用形成的“石海” ,与化学风化作用产生的花岗岩“石蛋”地貌特征 ,有天渊之别 ,不应混为一谈 ;边滩是由河流冲积物组成 ,不能与基岩冰床相提并论 ;圆滚水钻与急流旋涡及风蚀作用 ,形成的动力学性质、方向和方式完全不同 ,不该阴错阳差 ;节理、构造只影响冰臼的形态和发育程度 ,不是控制冰臼的发育部位 ,不致于是非不辨。南国地区古冰川遗迹的大量发现 ,证明距今约二三百万年的第四纪早期确实曾发生过大规模的古冰川运动 ,为争论了半个多世纪的中国东部中低山区有无第四纪冰川问题 ,从此画上一个圆满的句号。

The discovery of a host of glacial drifts, stratified pebbles and deformation gravel in the moulin groups area in South China once again provides strong evidence for the conclusion that the moulins are not a pot holes. The landform of “rock block fields”, which was formed after glacial erratic boulders were subjected to freeze thaw action (physical weathering), is completely different from the granitic pebbly landform,resulting from chemical weathering, thus these two cases cannot be confused. Concave flood plains are composed of river alluvia. Such plains and bedrock ice sills should not be mentioned in the same breath. Joints and structure give influence only on the form and development degree, but not on development position of the moulin. This means that truth and falsehood should not be confused. A great number of traces of former glaciers have been discovered in South China. This proves that a large scale glacial movement did take place in the early Quaternary ( ca.2-3 Ma B P.). Thus the debate on the question, whether Quaternary glaciers existed in mountainous areas with medium or low elevations in East and South China, which has been continuing for more than half a century, can be finished with success.