HN孔记录的淮北平原晚新生代8Ma以来气候及环境演化  

Climatic and environmental evolution recorded by HN borehole in Huaibei Plain since the Late Cenozoic (-8 Ma)

作　　者：张磊 胡道功[1,2,3] 秦小光[4,5,6] 邓成龙[5,7,8] 穆燕 李康康[4,5,8] 刘嘉麒 ZHANG Lei;HU Daogong;QIN Xiaoguang;DENG Chenglong;MU Yan;LI Kangkang;LIU Jiaqi(Institute of Geomechanics,Chinese Academy of Geological Sciences Beijing 100081,China;Key Laboratory of Active Tectonics and Geological Safety,Ministry of Natural Resources,Beijing 100081,China;Research Center of Neotectonism and Crustal Stability,China Geological Survey,Beijing 100081,China;Key Laboratory of Cenozoic Geology and Environment,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Institutions o f Earth Science,Chinese Academy of Sciences,Beijing 100029,China;CAS Center for Excellence in Life and Paleoenvironment,Beijing 100044,China;State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]自然资源部活动构造与地质安全重点实验室,北京100081 [3]中国地质调查局新构造与地壳稳定性研究中心,北京100081 [4]新生代地质与环境院重点实验室,中国科学院地质与地球物理研究所,北京100029 [5]地球科学研究院,中国科学院,北京100029 [6]生物演化与环境卓越创新中心,中国科学院,北京100044 [7]岩石圈演化国家重点实验室,中国科学院地质与地球物理研究所,北京100029 [8]中国科学院大学,北京100049

出　　处：《地质学报》2022年第3期1091-1103,共13页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号41807421,41372187,41772357);中国地质调查局地质调查项目(编号DD20190306)联合资助的成果。

摘　　要：淮北平原地处中国南北方过渡的关键带,该地区晚新生代沉积的深入研究不仅能为中国南北方过渡带古气候环境演化提供重要信息,而且能为构建中国晚新生代从东到西完整气候环境格局提供东部关键地区记录。但目前该区域晚新生代长尺度的气候环境记录非常缺乏。本文利用淮北平原HN钻孔沉积物岩性、粒度、磁化率、色度等分析结果,结合磁性地层年代学,重建了淮北平原约8.0 Ma以来的古气候及环境演化过程。淮北平原8.0-7.8 Ma气候较干热,为冲洪积相环境;7.8-7.0 Ma气候转为湿润,为深湖沉积环境;7.0-3.6 Ma气候为稳定的长周期的湿润—干旱交替波动,沉积环境为河—湖交替;3.6-2.7 Ma为湖泊—河流—河漫滩环境,该段时期气候在快速波动的过程中转型,气候向干旱化方向发展,这可能与此时全球气候变冷有关;2.7-1.7 Ma气候剧烈频繁波动,主要为河流相沉积环境;1.7-0.75 Ma气候相对稳定,是相对干旱的气候背景;0.75-0.55 Ma为湖沼沉积,冷湿的气候环境;0.55-0 Ma是相对干旱的气候,为泛滥平原沉积。本研究对重建中国南北方过渡带晚新生代气候环境演化具有参考意义,对理解晚新生代中国气候格局提供了东部地区新证据。Huaibei Plain is located in the key zone of the transition from south to north in China. The study of its late Cenozoic sedimentation can not only provide basic data for the evolution of paleoclimate and environment in the Huaihe River basin, but also provide key information for the reconstruction of a complete climate and environment pattern from east to west in the Late Cenozoic in China. The lack of records of the Late Cenozoic from the transition zone of north and south China has hindered our understanding of the paleoclimate and environmental evolution in the area. Based on the analytical results of lithology, grain size, magnetic susceptibility and chroma of HN borehole sediments in the Huaibei Plain, combined with chronology, the paleoclimate and environmental evolution processes in the middle reaches of the Huaihe River since about 8.0 Ma have been reconstructed. The climate of the Huaibei Plain was relatively dry and hot from 8.0 to 7.8 Ma, which was alluvial and pluvial facies environment;from 7.8 to 7.0 Ma, the climate became humid, which was a deep lake sedimentary environment;from 7.0 to 3.6 Ma, grain size, lightness, redness, and blueness were fluctuating with long period, denoting a river-lake alternation environment;the depositional environment was lake-river-floodplain environment from 3.6 to 2.7 Ma. The profiles of L^(*), a^(*) and b^(*) show simultaneous trends of gradually decreasing or increasing values during 3.6-2.7 Ma, and all the color proxies indicate an aridification trend in this region during this period, that maybe linked with global cooling. The grain size and L^(*), a^(*) and b^(*) were rapid and strong fluctuations indicating a rapid oscillating climate during the interval from 2.7 to 1.7 Ma. The climate was relatively dry from 1.7 to 0.75 Ma according to the lithology, grain size and color proxies analysis. From 0.75 to 0.55 Ma gray black silty clay indicate lake and marsh deposits, and the climate environment was cold and wet. In the last 0.55 Ma, part of the layers developed ca

关 键 词：晚新生代 沉积环境 古气候 淮北平原 淮河 

分 类 号：P532[天文地球—古生物学与地层学]