| Abstract: | Palynoflora studies on the Duantouliang section, located at 39º40'N, 103º55'E in Northwestern Tengger Desert, China showed that, based on the spore-pollen assemblages, the major vegetation and climatic environment between 42 000 to 23 000 a BP could be divided into the following different periods: Ⅰ. From 42 000 to 38 000 a BP, the spore-pollen assemblages displayed that the mixed conifer/deciduous broad-leaved forests developed on the mountain and its foothill regions where the bare Gobi-desert are at present; At that time, Populus and Salix forests and grassland surrounded the Paleaolake, the climate condition was much warmer and humid than today; Ⅱ. From 38 000 to 37 000 a BP, the climate was warm and moist, it was the most suitable period for the plant growth, the studied area was dominated by the temperate and warm-temperate mixed broad-leaf deciduous and needleleaf forest, there was meadow spreaded on the river sides and lake beaches; Ⅲ. From 31 000 to 30000 a BP, the needleleaf forests and cold-temperate Salix oritrepha shrubs were flourishing, and the climate at that time was relatively cold;Ⅳ. From 30000 to 28000 a BP, the temperatures began increasing, the high lake levels was formed during this time, and the vegetations were meadows and swamps; V. From 28 000 to 23 000 a BP, temperate Cupressaceae and Betula mixed conifer/deciduous forests grew on mountain and foothill region, grassland developed on plain areas, Salix was on lake and river sides. This indicates a warm and moist climate condition but it was drier than the earliest period. |
