吉林哈尼湖钻孔5000年以来的古植被气候变化指示

PALEOVEGETATIONAL AND PALEOCLIMATIC CHANGES IN HA'NI LAKE,JILIN SINCE 5 kaBP

选取哈尼湖钻孔360～0 cm（5 112 aBP以来）的沉积物进行孢粉分析,共采取样品85个,平均时间分辨率约为60 a.样品中花粉含量非常丰富,种类以乔木为主,其百分含量多在80%以上,最高可达96%,根据花粉组成在钻孔上的变化,结合花粉沉积率进行样品分析,自下而上可分为4个花粉组合带,进而将该区5 000 a以来气候演化大致分为4个阶段：阶段1（5 112～3 784 aBP）,阔叶类乔木占优势,湿生及水生草本比较丰富,气候温暖湿润;阶段2（3 784 ～1 380 aBP）,针叶类乔木占优势,湿生及水生草本消失,气候变凉干;阶段3 （1 380 ～994 aBP）,以松为主的针叶类仍占绝对优势,喜温湿的灌木草本含量持续下降,说明气候继续变冷变干;阶段 4（994 aBP以来）,植物种类比较丰富,湿生植物的沉积率明显增高,气候变得更加湿润.

According to the spore pollen analysis results of 85 core samples from Ha＇ni Lake,the history of vegetation and environment can be divided into four stages as follows. ①Stage Ⅰ （5 112-3 784 aBP） ： Broadleaved trees dominated in this stage, and the climate was warm and wet;② Stage Ⅱ （3 784-1 380 aBP） .The coniferous trees dominated during the whole stage, hydrophytic herbaceous plants disappeared, and the climate changed to be cold and dry;③ Stage Ⅲ （1 380~994 aBP）：The percent of coniferous trees continued to increase but hydrophytic herbaceous plants began to appear, suggesting that the climate was colder but a little more humid; ④Stage Ⅳ （994-0 aBP）. The diversity of plants was great, and the pollen sedimentation rate of hydrophytic herbaceous plants obviously increased, so the climate changed to be more humid.