摘要
河流沉积物蕴藏着其形成之时水动力条件及古气候变化等重要信息,因此研究河流相沉积物不仅可指示其沉积之时的水动力条件,还可对其反演的古气候进行一定的探索。伊逊河地处燕山东段,开展其下游河流相沉积物粒度、磁化率及形成年代的探讨,可为燕山山地河流相沉积物蕴藏的古环境意义研究提供参考。笔者等通过野外实地调查、光释光测年、粒度分析及磁化率实验对伊逊河下游三级阶地(T3)前缘剖面展开研究,初步确立了伊逊河下游T3的形成时间,大致为晚更新世晚期至全新世早期(13.14±0.76 ka BP至9.55±0.58 ka BP),结合野外实测及实验数据分析发现此剖面可划分为11层,探讨了伊逊河在晚更新世晚期至全新世早期水动力条件的变化,厘定了伊逊河下游9次较为明显的水文事件,并提出新仙女木事件始末及全新世初期此剖面沉积物记录与多种气候变化指标和区域气候变化有较高的一致性,揭示了伊逊河下游河流阶地沉积物对气候变化的响应较为明显,研究结果为该地区古环境研究提供了基础地质依据。
Objectives:River sediments contain important information such as hydrodynamic conditions and paleoclimate changes at the time of formation.Therefore,the study of river sediments can not only indicate the hydrodynamic conditions at the time of deposition,but also explore the paleoclimate inversion.Yixun River is located in the east section of Yanshan.The further study on the fluvial sediments in the lower reaches of Yanshan Mountains can provide some reference for the Paleoenvironmental Significance and research methods of the fluvial sediments in Yanshan Mountains.Methods:Through field investigation,optical luminescence dating,grain size analysis and magnetic susceptibility,T3 in the lower reaches of the Yixun River was studied.Results:Preliminarily established the formation time of T3 in the lower reaches of the Yixun River,which was roughly from the late Late Pleistocene to the early Holocene(13.14±76 ka BP to 9.55 ka BP±58 ka BP),and the grain size parameters and magnetic susceptibility were discussed.It was found that the T3 front section of lower reaches of the Yixun River could be divided into 11 layers,and the grain size characteristics of each layer were obvious,but the correlation with the magnetic susceptibility parameters was not enough.Secondly,by comparing the sediment grain size of the profile with the young Dryas events recorded by various climate change indicators,it is proposed that they have a strong correlation.The YD event is well recorded in the stratification FC3,and the FC1 corresponds to the warming process in the early Holocene.Finally,guided by the grain size of sediments and the characteristics of sediments on the profile,the changes of hydrodynamic conditions in the lower reaches of the Yixun River from the late Pleistocene to the early Holocene were discussed.Finally,based on the grain size and characteristics of sediments,the changes of hydrodynamic conditions in the lower reaches of the Yixun River from late Pleistocene to early Holocene are discussed.During this period,it is determined that there are nine obvious hydrodynamic events in the lower reaches of the Yixun River,and it is suggested that the sediments in the river terraces in the lower reaches of the Yixun River have obvious response to climate change.Conclusions:Based on the sediment characteristics,formation time,grain size and magnetic susceptibility of T3 front section in the lower reaches of the Yixun River,the hydrodynamic changes in the lower reaches of the Yixun River from late Pleistocene to early Holocene and the coupling relationship with paleoclimate,especially YD events are discussed.The purpose of this study is to provide reference for the study of sedimentary history of fluvial sediments and their response to paleoenvironmental changes in Yanshan Mountains.
作者
田钰琛
殷志强
张绪教
邵海
谷明旭
任伟
彭超
TIAN Yuchen;YIN Zhiqiang;ZHANG Xujiao;SHAO Hai;GU Mingxu;REN Wei;PENG Chao(School of Earth Sciences and Resources,China University of Geosciences,Beijing,100083;China institute of Geo-Environment Monitoring,Beijing,100081;Hebei geological environment monitoring Institute,Shijiazhuang,050021;The Fourth Geological Brigade of Hebei Bureau of Geology and mineral resources,Chengde,Hebei,067000)
出处
《地质论评》
CAS
CSCD
北大核心
2022年第1期111-121,共11页
Geological Review
基金
国家重点研发计划(编号:2018YFC1504704)
国家自然科学基金资助项目(批准号:41977258)
中国地质调查局地质调查项目(批准号:DD20190310)的成果。
关键词
伊逊河
阶地沉积物
粒度
光释光测年
古环境
Yixun River
terrace sediments
grain size
optically stimulated luminescence
paleoenvironment
