中中新世气候适宜期西北内陆干旱区气候演化特征  

Climate evolution of the Northwest China during Middle Miocene Climatic Optimum

作　　者：王海涛 吴福莉[1,3] 方小敏[1,2,3] 杨立业 WANG Haitao;WU Fuli;FANG Xiaomin;YANG Liye(Key Laboratory of Continental Collision and Plateau Uplift,Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100101,China;University of Chinese Academy of Sciences,Beijing 100049,China;CAS Center for Excellence in Tibetan Plateau Earth Sciences,Beijing 100101,China)

机构地区：[1]中国科学院青藏高原研究所大陆碰撞与高原隆升重点实验室,北京100101 [2]中国科学院大学,北京100049 [3]中国科学院青藏高原地球科学卓越创新中心,北京100101

出　　处：《地球环境学报》2020年第1期45-65,共21页Journal of Earth Environment

基　　金：中国科学院战略性先导科技专项(A类)(XDA20070201);国家自然科学基金重点国际合作研究项目(41620104002);第二次青藏高原科学考察(2019QZKK0707);青藏高原地球系统基础科学中心(41988101-01)。

摘　　要：中中新世气候适宜期是距离现今最近的一个未受人类活动影响的气候适宜阶段,现有记录大多显示全球在中中新世气候适宜期期间气候以暖湿为特征。我国西北内陆干旱区作为北半球中纬度面积最大的干旱带的重要组成部分,其气候如何响应全球中中新世气候适宜期的气候变化对预测全球变暖背景下西北内陆干旱区气候变化趋势及实现生态建设具有重要的指导意义。本文总结了西北内陆干旱区具有年代控制的15个剖面的孢粉、同位素、磁化率等19项记录,并选取各记录中指示意义明确的气候代用指标进行集成、分析,发现多数剖面在中中新世气候适宜期的不同时段出现了湿润化特征,但湿润化的出现、结束时间不同,自西向东,湿润事件结束(或适宜期后干旱化增强事件出现)的时间变晚。推测西北内陆干旱区中中新世气候适宜期的气候演化主要受全球气候变化影响,但湿润事件结束或适宜期后干旱化增强事件出现及其呈现出的时空差异则受区域构造活动及气候系统等因素控制。Background,aim,and scope The Middle Miocene Climatic Optimum is the most recent climatic optimum unaffected by human activity,when the climate was characterized as warm and humid.Northwest China is an important part of the largest arid region in the mid-latitude of Northern Hemisphere,and how did its climate respond to the global climate change during Middle Miocene Climatic Optimum is of great guiding significance,based on which we can predict the climatic change in Northwest China on the background of the global warming and build ecological construction.In this paper,we integrated the existing Middle Miocene sedimentary records in Northwest China,and we aimed to get the regional climate evolution characteristics of Northwest China and discuss how its climate responded to the global climate change and tectonic activity during Middle Miocene Climatic Optimum.Materials and methods We summarized 19 sedimentary records including sporopollen,isotope and susceptibility from 15 sections with age control in Northwest China,from which we selected the climatic proxies with clearly indicative meanings for integration and analysis.Results The majority of the selected sections presented humid climatic characteristic at different stages of Middle Miocene Climatic Optimum,and the ending time of wet episode generally became later from west to east,in other word,the occurrence time of the aridification enhancement that after Middle Miocene Climatic Optimum became later from west to east.Discussion Humid climatic stage can be identified in almost all of these Middle Miocene sections in the study area,which shows great similarity with global climate and implying its evolution was influenced by global climate change during Middle Miocene.However,the environmental gradient from west to east during Middle Miocene Climatic Optimum in the study area was possibly caused by climatic system differences and the gradually weakening of the East Asian summer monsoon.In addition,the temporal and spatial differences of the aridification occurre

关 键 词：中中新世气候适宜期 西北内陆干旱区 气候代用指标 全球变化 构造活动 

分 类 号：P532[天文地球—古生物学与地层学]