30 ka BP以来大兴安岭漠河盆地多年冻土区气候与环境变化  

Climate and environmental changes in the Mohe Basin permafrost region of the Greater Hinggan Mountains since 30 ka BP

作　　者：刘锐[1] 臧淑英[1] 赵林 吴晓东[3] 刘立新 吴少强 李天瑞 张紫豪 何俭翔 李彪 张博雄 程小峰 LIU Rui;ZANG Shuying;ZHAO Lin;WU Xiaodong;LIU Lixin;WU Shaoqiang;LI Tianrui;ZHANG Zihao;HE Jianxiang;LI Biao;ZHANG Boxiong;CHENG Xiaofeng(Heilongjiang Province Key Laboratory of Geographical Environment Monitoring and Spatial Information Service in Cold Regions,Harbin Normal University,Harbin 150025,China;School of Geographical Sciences,Nanjing University of Information Science and Technology,Nanjing 210044,China;Northwest Institute of Eco-Environment and Resources,CAS,Lanzhou 730000,China)

机构地区：[1]哈尔滨师范大学寒区地理环境监测与空间信息服务黑龙江省重点实验室,哈尔滨150025 [2]南京信息工程大学地理科学学院,南京210044 [3]中国科学院西北生态环境与资源研究院,兰州730000

出　　处：《地理学报》2024年第9期2280-2296,共17页Acta Geographica Sinica

基　　金：科技基础资源调查专项项目(2022FY100701);国家自然科学基金联合基金重点项目(U20A2082);国家自然科学基金项目(41971151);哈尔滨师范大学博士研究生创新基金项目(HSDBSCX2022-07)。

摘　　要：多年冻土对全球变化非常敏感,利用植被演替揭示多年冻土区气候与环境变化具有重要意义。本文以大兴安岭漠河盆地多年冻土岩芯孢粉学为证据,通过AMS14C构建了年代学框架,重建多年冻土区更新世晚期以来植被演替与气候历史,分析了植被演替对多年冻土区环境变化的响应。结果显示孢粉组合较好地反映漠河盆地和外围山地植被组成格局,依据区域关键植被对气候指示关系,漠河盆地30 ka BP以来植被演替指示气候发生了5次显著变化过程:30.0—27.1 ka BP形成草甸湿地景观,指示气候寒冷湿润;27.1—20.5 ka BP形成针叶林草原景观,指示气候相对寒冷干旱;20.5—11.3 ka BP由针叶林湿地向针阔混交林湿地景观转变,指示气温开始转暖,但气候仍寒冷湿润;11.3—1.9 ka BP形成针阔混交林湿地景观,指示气候温暖湿润;1.9 ka BP至今形成针叶林湿地景观,指示气候冷凉湿润。通过对比分析发现,影响植被演替的因素不仅包括纬度和海陆位置上的气候差异,还有多年冻土本身引起的区域环境效应,植被演替对冰期、间冰期多年冻土变化具有不同响应机制。在末次冰盛期,由于多年冻土冻结和扩张,导致多年冻土环境更能适应耐寒耐旱、根系较浅的蒿属、藜属等陆生草本繁殖,干旱草原扩张;在全新世大暖期,多年冻土的融化和退缩不仅为植被提供了良好的生境,还有利于湿地的潜育化和面积扩大,促进水生植被、蕨类苔藓和乔木的大量繁殖,形成森林湿地景观。因此,由于多年冻土的存在,放大了气候的水热特性,植被对多年冻土区环境变化的响应更为敏感。Permafrost is highly sensitive to global changes,and it is important to reveal climate and environmental changes in permafrost regions using vegetation succession.Based on palynological evidence and AMS14C dating from a sediment core,vegetation succession and climate history in the Late Pleistocene of the Mohe Basin(MHB)in the Greater Hinggan Mountain permafrost region was reconstructed.The response of vegetation to environmental changes was further investigated.Results showed that pollen assemblages effectively reflect the vegetation composition in the MHB and surrounding mountainous areas.Based on the relationship between key regional vegetation and climate indicators,vegetation has undergone significant historical changes:from 30.0 to 27.1 ka BP,a meadow wetland landscape showed a cold and humid climate;from 27.1 to 20.5 ka BP,a coniferous forest-grassland landscape indicated a relatively cold and arid climate;from 20.5 to 11.3 ka BP,there was a transition from coniferous forest wetlands to mixed coniferous-broadleaved forest wetlands,indicating the beginning of a warming although the climate remained cold and humid;from 11.3 to 1.9 ka BP,a mixed coniferous-broadleaved forest wetland landscape demonstrated a warm and humid climate;from 1.9 ka BP to the present,a coniferous forest wetland landscape revealed a cool and humid climate.A comparative analysis showed that factors influencing vegetation succession include not only climate conditions related to latitude and land-sea location but also regional factors caused by permafrost itself.Vegetation succession exhibited different response mechanisms to permafrost changes during glacial and interglacial periods.During the Last Glacial Maximum,permafrost expansion benefited the growth of cold and drought-resistant terrestrial herbs with shallow roots such as Artemisia and Chenopodiaceae,leading to the expansion of arid grasslands.During the Holocene Megathermal Period,permafrost degradation provided favorable habitats for vegetation,and also facilitated the formati

关 键 词：漠河盆地 更新世晚期 多年冻土 植被响应 古气候 

分 类 号：P642.14[天文地球—工程地质学] P467[天文地球—地质矿产勘探]