摘要
示踪黄河流域的泥沙来源,对于认识和理解青藏高原隆升剥蚀和西太平洋边缘海沉积之间的耦合关系至关重要。钾长石是河流沉积物中常见的造岩矿物之一,其铅(Pb)同位素比值在应用于大河物源示踪研究时效果良好,但这一研究在黄河流域还未开展。文中利用激光剥蚀电感耦合等离子质谱仪(LA-MC-ICP-MS)对黄河流域的15件样品进行分析,获得了967颗钾长石的原位Pb同位素结果。^(206)Pb/^(204)Pb和^(208)Pb/^(204)Pb比值二维散点图和多维判别图(MDS)结果表明,黄河玛多-同德段、大夏河和湟水的钾长石Pb同位素组成与黄河兰州段存在明显差异;黄河兰州段的钾长石Pb同位素组成与黄河巴彦淖尔段一致,二者受相似的风成物源区的影响;黄河晋陕峡谷段、汾河的钾长石主要来自黄土高原;渭河的钾长石主要来自秦岭。黄河开封和利津段的钾长石Pb同位素组成一致,都与黄河上游和华北板块明显不同,但与黄河中游相似。黄土高原对黄河中、下游的钾长石来源起主导作用。
The collision of the Indian plate with Eurasia in the early Cenozoic era drove the emergence of the Tibetan plateau.At the same time,the subduction of the western Pacific plate towards Eurasia resulted in the stretching and thinning of the lithosphere in eastern Asia,leading to a series of faulted basins and marginal seas.The macro-geomorphic pattern of East Asia was finally established under the control of these two tectonic domains.In this case,the Yellow River,which originated from the Tibetan plateau and flowed through the Loess Plateau and the North China Plain,carried a huge amount of detrital material into the Bohai Sea,which played an important role in the regional geochemical cycle,environmental change,sedimentary flux and the diffusion of detrital material in the shelf sea.Therefore,tracing sediment sources in the Yellow River Basin is of great importance for understanding the coupling relationship between uplift and denudation in the northeastern Tibetan plateau,East Asian monsoon evolution,and detrital material accumulation.However,the Yellow River Basin spans multiple climatic and tectonic zones with different provenance areas,so it is particularly critical to select appropriate provenance tracing methods.Although K-feldspar is more vulnerable to chemical weathering than zircon,it is a widely distributed rock forming mineral and can best represent the provenance characteristics of a certain area.The non-clay minerals in the Yellow River Basin are mainly composed of quartz and feldspar.At the same time,the Pb isotope ratios(^(206)Pb/^(204)Pb,207Pb/^(204)Pb and ^(208)Pb/^(204)Pb)of K-feldspar in different blocks are much different from those of Nd and Sr isotope systems and are often used to construct regional Pb isotope geochemistry province,continental crust evolution,and reconstruct paleocurrent direction,etc.In recent years,detrital K-feldspar Pb isotopic composition has been successfully used to trace the provenance of the Indus,Yangtze and Mississippi Rivers.But this method has not been carried o
作者
林旭
刘海金
刘静
吴中海
李兆宁
陈济鑫
李玲玲
胡程伟
LIN Xu;LIU Hai-jin;LIU-ZENG Jing;WU Zhong-hai;LI Zhao-ning;CHEN Ji-xin;LI Ling-ling;HU Cheng-wei(College of Civil Engineering and Architecture,Three Gorges University,Yichang 443002,China;Key Laboratory of Geological Hazards on Three Gorges Reservoir Area,Ministry of Education,China Three Gorges University,Yichang 443002,China;School of Earth Sciences,East China University of Technology,Nanchang 330013,China;School of Earth System Science,Tianjin University,Tianjin 300072,China;Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China;Institute of Geology,China Earthquake Administration,Beijing 100029,China)
出处
《地震地质》
EI
CSCD
北大核心
2022年第4期944-960,共17页
Seismology and Geology
基金
国家自然科学基金(41972212,42030305)
湖北省楚天学者人才计划(8210403)共同资助。
