末次冰期盛期中国热带的变迁

The Shift of Tropical Zone During The Last Glacial Maximum in China

参照约 60个实例 ,探讨末次冰期盛期中国热带位置的纬度地带性和经度地带性变迁。当时 ,热带中部、热带北部、亚热带南部 3个地带的北界分别南移 5个、 2个、 6个纬距。经度地带性差异可分为 5个区。其年均温下降幅度 ,台湾岛最大 ( 5～ 9℃ ) ,两广及海南岛其次 ( 3～4℃ ) ,闽南粤东较小 ( 2～ 3℃ ) ,滇南最小 ( 1～ 2℃ )。南海冬季水温降幅较大 ( 2 .4～ 5.7℃ )。除闽南、粤东、南海趋于冷干外 。

According to paleoenvironment analyses of about sixty samples including sporopollen, oxygen isotope, sedimentary, diatom, nannofossil, mammal, stalagmite, coral reef, glacial remain, etc., location changes of tropical and southern subtropical zones during the last glacial maximum in China are discussed in this paper. Comparing with present limits, the north limit of central tropics moved southward by five latitudes with an amplitude of drop in temperature of about 3℃. The north limit of northern tropics moved southward by two latitudes and the drop in temperature was less than 2℃. The north limit of southern subtropics experienced the largest moving distance and amplitude in temperature drop, being the six latitudes and four degress respectively. The longitude zonal differentiation is also obvious. Five regions can be divided from east to west. The largest amplitude of temperature drop is 5～9℃ in Taiwan Island, and the second is 3～4℃, occurring in Guangdong, Guangxi and Hainan provinces. The drop amplitude in water temperature of 2 4～5 7℃ in winter was considerably large in the South China Sea but its summer temperature was similar to that at present. In soutern Fujian and eastern Guangdong the amplitude was relative small, being 2～3℃, and the minimum of 1～2℃ was only found in southern Yunnan. The paleoenvironmental conditions at that time tended to be more cold and wet generally except southern Fujian and South China Sea where the trend was cold and dry. The drop in temperature in China’s tropical zones is a result of the uplift of the Tibetan Plateau with an accelerated rate of 11 8～15 7 mm/a during the late Pleistocene which aggravated the worsening of climate during glacial period.