安徽省池州地区距今3万年以来古植被演替过程及晚全新世人类活动的影响

Paleovegetation succession over the past 30000 yr and human activities during the late Holocene in Chizhou city,Anhui Province

通过对长江下游安庆池州市地区钻孔岩芯开展古环境变化研究,基于岩芯5个沉积物样品的AMS14C测年结果建立沉积深度-年龄框架,根据孢粉分析结果探讨研究区域MIS3晚期以来古植被演变过程,并分析了全新世晚期人类活动对植被的干扰信号。研究结果表明:1)在MIS3阶段晚期(~30540~25330 cal a BP),研究区域植被类型表现为常绿落叶阔叶混交林,优势种类以壳斗科常绿类型青冈属和松属植物为主,落叶栎属和栗/锥属植物相对较少,反映了当时气候为温暖湿润;2)在MIS2阶段(25330~9640 cal a BP),研究区域植被以落叶阔叶林为主要特征,该阶段气候从末次盛冰期时期的寒冷干燥逐渐转变为温凉湿润;3)在早-中全新世阶段(9640~5180 cal a BP),森林植被开始繁盛,尤其是乔木类植物含量达到峰值,反映出当时气候温暖潮湿;4)在晚全新世阶段(5180 cal a BP以来),禾本科植物花粉(>40μm)剧增,可能与当时稻作农业规模增大有关;同时乔木类花粉锐减,反映了人类活动对自然植被干扰强度增加。

Based on AMS14 C dating results of five samples of drilling core GMD06,the sedimentary framework of the age-depth of Chizhou,Anhui Province,was established.The pollen analysis data reveal the vegetation succession history in this Yangtze River basin since the late MIS3.During the late MIS3 period(~30540-25330 cal a BP),the vegetation type of the study area was evergreen deciduous broad-leaved mixed forest;the dominant species were Cyclobalanopsis and Pinus,while the Quercus-deciduous and Castanea/Castanopsis were relatively less;and the climate was warm-cool and humid.During the MIS2 period(25330-9640 cal a BP),the vegetation was mainly characterized by deciduous broad-leaved forest;the climate gradually changed from cold and dry to cool and wet during the last glacial maximum.During the early and middle Holocene(9640-5180 cal a BP),the vegetation began to flourish,particularly,the tree pollen reached the peak;the climate was warm and humid.During the late Holocene(~5180 cal a BP),the Poaceae(>40μm)pollen increase significantly which probably indicates the increased rice agricultural activities;coupled with the sharp decreasing of tree pollen,it suggests the intensified disturbance of natural vegetation by human activities.