摘要
黄河入海口位于海陆过渡带,对环境变化响应敏感,揭示其沉积环境特征,对于探讨区域气候环境演变与高质量发展具有重要意义。通过对黄河入海口垦利(KL)岩芯的AMS14C测年、岩性、粒度、磁化率、碳氮比(w(TOC)/w(TN))等分析,重建了黄河入海口地区全新世以来的沉积环境特征。结果表明,KL岩芯覆盖过去9.28 ka,岩芯反映的黄河入海口地区全新世沉积环境经历了5个阶段:约9.28~8.15 cal ka BP,颗粒较粗,磁化率值较高,w(TOC)/w(TN)较大,陆源输入强烈,为河流作用主导的三角洲沉积;约8.15~7.37 cal ka BP,沉积物颗粒变细,w(TOC)/w(TN)较小,表明来源于温暖湿润环境的水生有机物输入量增加,此时研究区转变为滨海相沉积环境;约7.37~3.19 cal ka BP,陆源沉积逐步增加,粒度波动频繁,磁化率值降低,有机来源混合,沉积环境开始向陆相沉积过渡;约3.19~0.82 cal ka BP,持续的陆源沉积,粒度稳定,磁化率上升,反映了气候变冷和人类活动的增强;约0.82 cal ka BP至今,岩性均一,有机质含量低,磁化率高,表明稳定的陆源沉积系统基本形成。文章揭示了自然和人类活动共同影响下的黄河入海口环境演变过程,对未来区域环境预测有重要的指示意义。
The Yellow River Estuary,situated in a land-sea transition zone,is highly sensitive to environmental changes.Understanding the sedimentary environmental characteristics is crucial for exploring regional climate-environmental evolution and supporting high-quality development.Through analyses of AMS14C dating,lithology,particle size,magnetic susceptibility,TOC/TN,and other proxies on the Kenli borehole from the Yellow River estuary,the sedimentary environmental characteristics of this region have been reconstructed since the Holocene.The results indicate that the KL core spans the past 9.28 ka,revealing five distinct stages in the Holocene sedimentary environment of the Yellow River Estuary.From approximately 9.28 to 8.15 cal ka BP:Sediments exhibited coarser grain size,higher magnetic susceptibility,and higher TOC/TN ratios,indicating intense terrigenous input within a deltaic depositional environment dominated by fluvial processes.From approximately 8.15 to 7.37 cal ka BP:Grain size became finer and TOC/TN ratios decreased,suggesting an increased input of warm-humid aquatic organic matter.During this period,the area transitioned to a littoral sedimentary environment.From approximately 7.37 to 3.19 cal ka BP:Terrigenous sedimentation gradually increased,marked by frequent grain size fluctuations,declining magnetic susceptibility,and mixed organic matter sources.This reflects the onset of a transition to a terrestrial sedimentary environment.From approximately 3.19 to 0.82 cal ka BP:Persistent terrigenous sedimentation occurred alongside stable grain size and rising magnetic susceptibility.These changes indicate a cooling climate and intensified human activity.From approximately 0.82 cal ka BP to present:Uniform lithology,low organic matter content,and high magnetic susceptibility point to the establishment of a relatively stable terrigenous sedimentary system.This study elucidates the environmental evolution of the Yellow River estuary under the combined influences of natural processes and human activities.These findings have significant implications for predicting future regional environmental changes.
作者
许非凡
陈影影
魏歌颂
陈诗越
XU Feifan;CHEN Yingying;WEI Gesong;CHEN Shiyue(School of Geography,Geomatics and Planning,Jiangsu Normal University,Xuzhou 221116,China)
出处
《华南地理学报》
2025年第3期18-28,共11页
South China Geographical Journal
基金
国家自然科学基金项目(41871073)
江苏师范大学研究生科研创新计划项目(2025XKT1037)。
关键词
黄河入海口
全新世
沉积相
环境演化
estuary of the Yellow River
Holocene
sedimentary facies
environmental evolution
