摘要
本文报道了四川盆地白垩纪沙漠古风向测量结果，总结了风向变化的规律。认为该沙漠早期处于副热高压带地区的西风和东北信风切变带（ｄｉｖｅｒｇｅｎｔｌａｔｉｔｕｄｅｓｏｆｗｅｓｔｅｒｌｙｗｉｎｄｓａｎｄｎｏｒｔｈｅａｓｔｅｒｌｙｔｒａｄｅｗｉｎｄｓ）。随着气候的波动，该切变带发生了短周期的南北向漂变，造成西风与东北信风交替现象。该沙漠的晚期，由于气候的长周期波动，切变带南移，整个沙漠完全被西风带控制。从大气环流样式演变出发，讨论了东亚地区白垩纪以来气候变化的主要原因，认为青藏高原隆升前控制东亚地区的为行星环流，为干旱气候；青藏高原隆升之后改变了原有大气环流样式，建立了东亚季风环流，使干旱气候转变为潮湿气候。四川盆地白垩纪古风向测量填补了青藏高原隆升前东亚大气环流样式地质证据的空白，具有重要的科学意义。
The present paper deals with the measurements and variations in palaeowind direction of the Cretaceous desert in the Sichuan Basin. The desert was in the divergent latitudes of westerly winds and northeasterly trade winds in the subtropical high pressure belts during the early stage of the desert. The short period NS drifts of the divergent latitude in response to the climatic fluctuations are responsible for the alternation of westerly winds and northeasterly trade winds. Till the late stage of the desert, the divergent latitudes was drifted southwards due to the lond period climatic fluctuations and thus the whole desert was within the extent of the westerly winds. Finally the climatic changes in East Asia from the Cretaceous onwards are also discussed. The authors contend that planetary circulations and dry climates once prevailed over East Asia prior to the uplifting of the Qinghai Xizang Plateau. This situation, however, has been changed since the uplifting of the plateau, e.g. from planetary circulation patterns into monsoon circulation and from dry climate into humid climate. The measurements of the palaeowind direction of the Sichuan Basin during the Cretaceous have supplied the geological data on the atmosphere circulations in East Asia prior to the uplifting of the Qinghai Xizang Plateau, and thus are of great scientific importance.
基金
国家自然科学基金
地矿部沉积盆地与流体动力学开放实验室资助项目
关键词
四川盆地
白垩纪
沙漠
风向变化规律
Cretaceous desert
palaeowind direction
divergent latitude of westerly winds and northeasterly trade winds
evolution of the atmospheric circulation patterns and climatic changes in East Asia〖H
