西藏札达盆地古格剖面孢粉记录及其反映的古环境信息

Sporopollen records in the Guge section of the Zanda basin,Tibet,and paleoenvironmental information reflected by it

通过对西藏札达盆地上新世古格剖面的孢粉分析,上新世古格组地层沉积物记录了4.40～2.74 Ma时期该地区的植被与环境演化过程。4.40～3.75 Ma时期,气候温凉而干旱,呈现出暖温带针阔叶混交疏林植被景观;3.75～3.47 Ma时期,属于山地暖温带针阔叶混交林,气候由温凉干旱向温暖湿润过渡;3.47～3.20 Ma时期,植被发育,属于针阔叶混交林,气候以温暖湿润为主;3.20～2.96 Ma时期,植被以山地暖温带针阔叶混交林与山地寒温带针叶林交替变化为特征,气候开始向干冷方向发展;2.96～2.74 Ma时期,属山地寒温带暗针叶林特征,气候持续干冷。

The palynological records of the Pliocene Guge section in the Zanda basin, Tibet, show that the Guge section registers the process of vegetational and environmental variation in the study area from 4.40 to 2.74 Ma. During 4.40-3.75 Ma the climate was cool and dry and there appeared the landscape of needleleaf and broadleaf reid vegetation; during 3.75-3.47 Ma the vegetation belonged to mountainous, warm-temperate, mixed needleleaf and broadleaf forest and the climate changed from cool-dry to warm-moist; during 3.47-3.20 Ma the vegetation grew well, belonging to the mixed needleleaf and broadleaf forest, and the climate was mainly wetwarm; during 3.20-2.96 Ma the vegetation was characterized by alternation of mountainous, warm-temperate, mixed needleleafand broadleaf forest and cool-temperate needleleaf forest and the climate began to become drycold; during 2.96-2.74 Ma the vegetation was characterized by mountainous, cool-temperate, dark needleleaf forest and the climate kept dry and cold.