贵州草海0.78 Ma以来古环境演化:来自XRF连续扫描的证据  

The paleoenvironmental evolution since 0.78 Ma in Caohai,Guizhou:evidence from XRF core scanning

作　　者：许聿迪 刘承帅 高庭 刘彧 尹润生[1] 孙蕗 XU Yudi;LIU Chengshuai;GAO Ting;LIU Yu;YIN Runsheng;SUN Lu(State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China;University of Chinese Academy of Sciences,Beijing 100049,China;South China Agricultural University,College of Natural Resources and Environment,Guangzhou 510642,China;East China University of Technology,School of Earth Sciences,Nanchang 330013,China)

机构地区：[1]中国科学院地球化学研究所环境地球化学国家重点实验室,贵州贵阳550081 [2]中国科学院大学,北京100049 [3]华南农业大学资源环境学院,广东广州510642 [4]东华理工大学地球科学学院,江西南昌330013

出　　处：《地学前缘》2025年第3期168-182,共15页Earth Science Frontiers

基　　金：国家自然科学基金项目(42330712)。

摘　　要：云贵高原地区气候受到不同季风的显著影响,变化趋势较为复杂。为探究该地区环境变化与全球气候变化的内在联系,本研究选取贵州草海湖泊沉积柱2023CH(D)为研究材料,通过高分辨率X射线荧光(XRF)连续扫描和古地磁分析,结合磁化率、粒度及Al、Si、K、Ca等元素的多元统计分析结果,对草海地区0.78 Ma以来的古环境演化进行探讨。研究发现0.78 Ma以来草海的古环境演化可划分为5个阶段:Ⅰ阶段(0.78~0.66 Ma),草海地区气候基本响应全球气候变化;Ⅱ阶段(0.63~0.33 Ma)草海区域气候在全球气候主导的基础上,也明显响应地轴倾角和岁差周期;Ⅲ阶段(0.32~0.22 Ma)为相对温和的冰期凉湿气候,条件适宜碳酸盐岩大量淋溶;Ⅳ阶段(0.21~0.12 Ma)总体呈现冷干气候,早晚两段偏暖湿,物理和化学风化的相对强度均较好地响应岁差周期;Ⅴ阶段(0.12~0.02 Ma)整体趋于冷干,但气候在亚轨道尺度上于冷干-暖湿之间快速振荡,且波动幅度呈增大趋势。草海的气候演化同时受到轨道周期和亚轨道周期影响,不同古环境代用指标对轨道周期的响应存在差异。植被覆盖率受亚洲季风强度的显著影响,其变化主要受全球气候的调控,而物理风化、化学风化相对强度和降雨量对倾角和岁差周期响应更敏感。草海地区气候波动呈现频率更快且更加极端的趋势。总体而言,草海地区气候对全球变化的响应较为复杂,其背后的驱动机制尚需进一步探讨。The climate of the Yunnan-Guizhou Plateau is significantly influenced by diverse monsoon systems,displaying a complex pattern of climatic changes.This study investigates the relationship between local environmental changes and global climate dynamics using sediment core 2023CH(D)from Caohai Lake in Guizhou Province.Employing high-resolution X-ray fluorescence(XRF)scanning and paleomagnetic dating,combined with multivariate statistical analysis of magnetic susceptibility,grain size,and elemental data(including Al,Si,K,Ca,etc.),this research explores the paleoenvironmental evolution of the Caohai region since 0.78 Ma.The findings identify five climatic phases:1)Stage I(0.78-0.66 Ma),where the local climate essentially mirrored global climatic changes;2)Stage II(0.63-0.33 Ma),dominated by global climate patterns but significantly modulated by Earth’s obliquity and precession cycles;3)Stage III(0.32-0.22 Ma),characterized by a relatively mild glacial climate with cool,humid conditions that substantially promoted carbonate leaching;4)Stage IV(0.21-0.12 Ma),predominantly cold and dry,with initial and final phases experiencing slightly warmer and more humid conditions,reflecting precession cycles in the relative intensity of physical and chemical weathering;5)Stage V(0.12-0.02 Ma),generally trending towards colder and drier conditions,yet characterized by rapid oscillations between cold-dry and warm-humid states on sub-orbital scales,with an increasing amplitude.The climatic evolution in Caohai is influenced by both orbital and sub-orbital cycles,with varying responses among different palaeoenvironmental proxies.Vegetation coverage,primarily controlled by the intensity of the Asian monsoon and global climate conditions,exhibits sensitivities to these cycles,while variations in the intensity of physical and chemical weathering and precipitation are more closely aligned with obliquity and precession cycles.The climatic fluctuations in the Caohai region have shown a trend towards increased frequency and extremity.Overall

关 键 词：云贵高原 湖泊沉积 XRF连续扫描 元素地球化学 古环境演化 

分 类 号：P534.63[天文地球—第四纪地质学] P539.3[天文地球—古生物学与地层学] P595[天文地球—地质学]