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两种对立的观点 在地质学家看来,造山运动就是造陆运动。这一点从欧洲和北美洲的造山带分布中可以看得很清楚。在欧洲,中部加里东至海西造山带(距今4.5～2.5亿年)和南部阿尔卑斯造山带(距今不足1.5亿年),依次紧贴在北部由前寒武纪地层(距今27～10亿年)构成的斯堪的纳维亚地质节上。在北美洲,距今32～27亿年的“苏必利尔”古陆核依次受到年龄为18亿年的“丘吉尔区”和年龄为12～9亿年的“格林维尔区”的紧紧包围。每一期山脉之下一般均见有更老的花岗岩基底。由此就地球上陆地的生成问题产生了两种截然对立的观点。一种观点认为,每期山脉都
Two Oppositional Views To geologists, orogeny is the land-building movement. This can be seen clearly in the distribution of orogenic belts in Europe and North America. In Europe, the eastern Caledonian to Hercynian orogenic belts (4.5-2.5 billion years ago) and the southern Alps orogen (less than 1.5 billion years ago), followed by the Precambrian strata in the north (27 ~ 1 billion years) constitute the Scandinavian geological festival. In North America, the ancient Superior Silicon Valley, 3.2 to 2.7 billion years ago, is in turn surrounded by the 1.8 billion-year-old Churchill area and the 1.2-300 billion-year-old Greenville District. Under each mountain range there is generally an older granite basement. Thus there are two diametrically opposed views of the formation of land on earth. A view that each period of the mountains are