应用柴达盆地西部大浪滩梁ZK02孔岩芯,依据铀系年龄数据,选择130 ka BP(90.5 m以上)的含石膏粉砂淤泥层中34个样品进行孢粉分析研究,依据其孢粉组合特征,将该孔深90.5m以浅的孢粉百分比图式从下至上划分6个区域性孢粉带,进而分析了该区末次间冰期(130 ka BP)以来的古植被状况,结果表明,山地主要由松、云杉、冷杉等组成的寒温性针叶林覆盖,而盆地则主要是以蒿、菊、禾本科等中旱生草本植物组成的温性草原,总体上反映了该区130 ka以来代表冷干气候的5次成盐期及其所夹的6次温湿期变化韵律,由此可以推测,该区主要植被和古环境的进程很可能源于东亚夏季风的减弱或增强,其气候旋廻大致可以和青海湖QH-86孢粉分析所揭示的130 ka以来古植被演替及深海氧同位素第三阶段乃至黄土磁化率所反映的6个夏季风增强的时段进行对比。
To provide information on vegetation patterns and altitudinal distributions of pollen assemblage in surface soil layers,their complicated relationships in a dryland mountain-basin system in northwestern China and a realistic basis for paleovegetational reconstruction,we investigated 86 vegetation quadrats and analyzed 80 soil samples from the surface soil layers along an altitudinal transect on the north slope of the Middle Tianshan Mountains from alpine cushion vegetation at 3,510 m near glacier to desert vegetation at 460 m in the Gurbantunggut Desert.According to surface pollen assemblages and the results of the detrended correspondence analysis,the transect can be divided into six major altitudinal pollen zones as alpine cushion vegetation,alpine and subalpine meadows,montane Picea forest,forest-steppe ecotone,Artemisia desert and typical desert,which basically reflect the characteristics of the mountainous vegetation patterns on the north slope of the Middle Tianshan Mountains.However,Picea pollen also exists outside the spruce forest,Chenopodiaceae and Artemisia pollen appeared above the elevation of 1,300 m,indicating that most of them might be introduced from lower elevations by upslope winds.Airborne pollen researches from three regions at different elevations further suggest that a high-frequency northwest anabatic wind has a remarkable influence on the transportation and dispersion of surface pollen in the area.
YANG ZhenjingZHANG YunREN HaibaoYAN ShunKONG ZhaochenMA KepingNI Jian
