摘要
关于冰臼① 形成与保存机理认识上的误区 ,主要包括冰臼三种生成模式 :冰川压融水—水刀切割模式、水应力集中一点模式、滴水穿石模式等 ,以及冰臼能保存至今的三论 :花岗岩抗蚀论 ,与旧石器比较论 ,冰碛物覆盖论。文中认为急流漩涡模式和瀑布模式是壶穴、冰臼生成的模式 ;揭西石肚溪所谓平缓基岩冰床 ,其实是该V形谷底宽 10～ 30m的花岗岩边滩 ,河床中所谓冰川漂砾 ,其实是山洪和块体运动带来的本流域大漂石 ,所谓漂砾碛及石海 ,其实是该谷坡上的花岗岩石旦地貌 ;发育深切曲流—交错山咀和V形峡谷证明丰顺龙鲸河是山区河流 ,这两河的谷底见壶穴而不是冰臼 ;说昔日冰臼能保存至今是不符合广东新构造运动和地貌发育史规律的。
There are some mistaken views in cognition of moulin formation and conservation. Three models for moulin′s formation were raised: 1) the glacial meltwater under high pressure served as a water knife cutting the rock to form the moulin; 2) the stress of water was focussed on one point and produced torrent whirlpool cutting the rock; 3) the glacial meltwater that moved down along glacial fissures dripped constantly onto the stone and wearing holes in it. Also three arguments about the reasons why the moulins that formed 2～3 Ma B P. can be conserved so far were advanced: 1) the granite is strong in resisting erosion; 2) the moulins were overlaid with huge thickness of till during the later interglacial stage, which was not removed until 2000 a B P.; 3) as compared with the stone implement of the Old Stone Age buried in karst caves that is still intack so far, the moulins can also be conserved for such a long time. It is considered that those models and arguments are false. They are not of fact basic and contravene the basis theory of geoscience. The so called “glacial bedy” along the Shidu Brook at Poxia Village, Jiexi County, is in fact the granite overflow-land with 10-30 m in width at the bottom of a V-shaped valley, where there are many pot-holes. The so-called “glacial boulder” in the river bed is actually the large granite boulder carried by torrents from the mountain to the valley. And, the “boulder ridge and stone field” are in fact the landform of eroded granite eggs on the slope. It is proved that the Longjing River in Fengshun County is only a common river with V-shaped gorge in mountain area, not a U-shaped glacial valley. Those arguments about the long-period conservation of the moulins are out of accord with the laws of neotectonism and geomorphic development history in Guangdong.
出处
《热带地理》
北大核心
2000年第2期156-161,共6页
Tropical Geography
关键词
壶穴
冰臼
广东
保存机理认识
误区
Pot-hole
Moulin
Mistaken views in cognition
Guangdong
Hebei-Neimeng
