柴达木盆地北缘古-新近纪河湖相沉积物颜色的气候意义  

The Climatic Significance of the Color of the Paleo-Neogene Fluvial and Lacustrine Sediments in the Northern Qaidam Basin

作　　者：李星波 季军良[1] 曹展铭 王朴[3] 吴武军[3] 孙玲[1] Li Xingbo;Ji Junliang;Cao Zhanming;Wang Pu;Wu Wujun;Sun Ling(School of Geography and Information Engineering,China University of Geosciences,Wuhan 430078,China;The Fifth Oil Production Plant,Qinghai Oilfield Branch of CNPC,Haixi 816499,China;Research Institute of Petroleum Exploration and Development-Northwest,PetroChina,Lanzhou 730020,China)

机构地区：[1]中国地质大学地理与信息工程学院,湖北武汉430078 [2]中国石油青海油田分公司采油五厂,青海海西816499 [3]中国石油勘探开发研究院西北分院,甘肃兰州730020

出　　处：《地球科学》2021年第9期3278-3289,共12页Earth Science

基　　金：中国地质调查局项目(No.DD20190370);国家油气重大科技专项(No.2016ZX05003⁃006).

摘　　要：柴达木盆地厚达万米的新生代沉积物记录了青藏高原东北部隆升和古气候变化信息.本文基于盆地北缘大红沟剖面高分辨率的磁极性年代标尺,对该剖面古‒新近纪河湖相沉积物进行了颜色测量,首次获得了柴达木盆地长时间尺度(52~7 Ma)的色度参数变化序列.在此基础上,综合沉积相与区域构造和古气候记录,探讨了影响河湖相沉积物颜色参数的因素及柴达木盆地古‒新近纪的气候演变.结果表明,大红沟剖面沉积物颜色的变化与全球温度变化趋势基本一致,说明温度是影响颜色参数,特别是红度(a*)的主要因素;沉积相变化,尤其是水面上、下的氧化‒还原环境变化对颜色参数也有重要影响.根据色度参数在时间标尺上的变化,将柴达木盆地的气候变化划分为8个阶段:(a)52.0~44.2 Ma湿热,(b)44.2~33.7 Ma在干湿波动中逐渐变干,(c)33.7~27.1 Ma进一步变干,(d)27.1~19.7 Ma逐渐变湿,(e)19.7~17.0 Ma较干旱,(f)17.0~13.3 Ma气候湿润,(g)13.3~9.5 Ma快速变干,(h)9.5~7.0 Ma进一步变干旱.影响柴达木盆地古‒新近纪气候变化的主要因素包括全球温度、副特提斯海、青藏高原构造隆升和东亚夏季风.Cenozoic sediments up to 10000 meters thick in the Qaidam basin recorded the Tibetan plateau uplift and paleoclimate changes.Based on the high-resolution magnetic polarity dating scale of the Dahonggou section in the northern margin of the basin,the color measurement of the Paleo-Neogene fluvial and lacustrine sediments in this section is performed.Furthermore,integrating the sedimentary facies,regional tectonic and paleoclimate records,this paper discusses the factors affecting the color parameters of river-lacustrine sediments and the climate evolution of the Qaidam basin during the Paleo-Neogene period.The research results show that the change of sediment color in Dahonggou section is basically consistent with the global temperature trend,indicating that temperature is the main factor affecting color parameters,especially the redness(a*)value,but the sedimentary facies changes,especially changes in the oxidation-reduction environment above and below the water,also have an important influence on the color parameters.According to the changes of color parameters on the time scale,the climate change in the Qaidam basin has been divided into 8 stages:(a)hot and humid during 52.0-44.2 Ma,(b)gradually becomes dry in the fluctuation of dryness and wetness during 44.2-33.7 Ma,(c)further dries during 33.7-27.1 Ma,(d)gradually becomes wet during 27.1-19.7 Ma,(e)relatively dry during 19.7-17.0 Ma,(f)warm and humid during 17.0-13.3 Ma,(g)rapidly dries during 13.3-9.5 Ma,(h)becomes further arid during 9.5-7.0 Ma.The main factors affecting the Paleo-Neogene climate change in the Qaidam basin include global temperature,the Para-Tethys Sea,the uplift of the Tibetan plateau and the East Asian summer monsoon.

关 键 词：青藏高原 柴达木盆地 古‒新近纪 颜色 古气候 地层学 

分 类 号：P532[天文地球—古生物学与地层学]