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有了大量的沙,形成沙漠是非常容易的。不过,在地质史上,每个沙漠的背后似乎总是有另一种因素。除了高纬度或高海拔地区、雨影区或冰封地区的某些特殊情况外,沙漠主要有两类:即海岸沙漠和与赤道半永久性高压带有关的内陆沙漠。内陆沙漠的沙主要来源于那些季节性河流。这些河流通常只在湿润气候期间发水并重新聚积以前的沙。而海岸沙漠的沙则来自那些在退潮时受风力作用的潮间海滩和大陆架。因此,通过对古代和现代沙漠的研究,我们更多地了解了气候。
With a lot of sand, forming the desert is very easy. However, in the history of geology, there seems to always be another factor behind each desert. Except for some special cases of high latitude or high altitude, rainy areas or frozen areas, there are mainly two types of deserts: the coastal desert and the inland desert associated with the equatorial semi-permanent high pressure belt. The sand in the inland desert mainly comes from those seasonal rivers. These rivers usually only send water during humid climates and regain their previous sand. The sand in the coastal desert comes from the intertidal beaches and continental shelves that are affected by the wind at low tide. Therefore, by studying the ancient and modern deserts, we learned more about the climate.