摘要
陆架沙漠化理论主要有两方面的问题：第一，该理论所例举的沙漠化证据大多属于不能确认沙漠环境的多解标志；第二，该理论没有阐明冰后期海进过程对陆架上可能存在的风成沙所产生的影响。本文就这些问题进行了讨论。
Since 1991, some scholars have proposed the hypothesis that at the end of the late Pleistocene when the sea level was low and glaciation reached its maximum, the environment of China's continental shelf was once a desert. The idea has been used to interpret the formation of the remnant deposits in the shelf region. The main evidence includes the presence of uniform disintegration of marine strata, extensive mixed deposits, long erosional basal plane, repose angle type of structure, buried dune groups and ventifacts. We contend that whereas the idea has some merit when the environment at that time is seen at the macro scale, the evidence submitted thus far is not convincing. Moreover, the idea does not take into consideration the possible impact of aeolian sand on the environment during marine transgression in the post glacial period. On this issue, we offer three views. (1) In the absence of biological evidence, to distinguish aeolian sand facies (ancient sand dunes) from the desert environment (ancient desert) should follow the principle of using multiple indices, and the indices selected should be able to diagnose landform processes and environmental features. But thus far much of the evidence proposed to support the hypothesis such as the “buried sand dune groups” is not unique to desert environment. (2) Although ventifacts (aeolian gravel) do indicate strong aeolian activities, they are not the only indicator of an arid desert environment. A comparative analysis of the grave forms and surface texture of the gravel from the seabed of the South Sea with the ventifacts of a modern desert environment shows that they differ markedly. They should not be regarded as the same thing. (3) Under the dry and cold glacial climate, aeolian sand (sand dunes) does not speedily cemment and diagenize into rocks. In addition, aeolian san (sand dunes) was highly susceptible to damage and change by marine trnasgression during the post glacial period. Thus it is not likely that sediment structure such as repose angle type of structure and sand dune morphology such as buried sand groups could be preserved in large areas. In short, the remnant deposits on China's continental shelf should not be seen as ancient desert deposits. GEOGRAPHY RESOURCES AND THEIR EXPLOITATION IN THE INTERNET$$$$ Chen Youfei (Department of Geography, Fujian Normal University, Fuzhou 350007) Xu Shiyuan (Department of Geography, East China Normal University, Shanghai 200062)
出处
《地理学报》
EI
CSCD
北大核心
1999年第3期269-276,共8页
Acta Geographica Sinica
关键词
陆架沙漠化
沙漠
风成沙
风棱石
海面变化
Internet, Internet resources, geography Abstract Internet is becoming more and more important in geography research. This makes it possible for geographers to do their research by international cooperation and thus to probe deeply into the essence of
