松花江流域河流沉积物碎屑锆石U-Pb年龄对物源示踪的启示OA
Implications of detrital zircon U-Pb ages in the sediments of the Songhua River basin for provenance tracing
河流沉积物是源-汇系统分析和古地理重建的重要载体,其沉积信号在搬运过程中易受支流稀释和锆石产率差异的影响.传统物源分析多忽略支流稀释效应和锆石产率的差异,导致结果出现偏差.目前,松花江流域内支流汇入对干流碎屑锆石年龄变化的控制机制及其沉积贡献的定量评估尚未明确.本研究对松花江干流以及嫩江、吉林松花江和拉林河支流开展碎屑锆石 U-Pb年代学研究,并结合稀释度指数、锆石产率校正及逆向蒙特卡洛模型,探讨松花江流域源-汇系统.结果表明,河流沉积物碎屑锆石U-Pb年龄主要集中于202～110 Ma、523～205 Ma、2066～1564 Ma、2747～2341 Ma四个年龄段.支流稀释和锆石产率差异是影响碎屑锆石年龄变化的主要因素.其中,支流稀释效应随搬运距离的增加逐渐减弱,锆石产率校正可以解决因源区锆石产率差异导致的沉积通量偏差问题.本研究提出两点物源示踪建议:一是采样应避开河流交汇处,优先选择距交汇处至少50～100 km的河段,二是物源分析需先进行锆石产率校正,以提高结果的准确性.锆石可再现性分析显示吉林松花江碎屑锆石缺少1800 Ma年龄信息,表明仅依赖碎屑锆石年龄峰值无法全面反映区域岩浆构造事件.本研究引入支流稀释和锆石产率两大因素,并将碎屑锆石和岩浆锆石年龄结合,有效避免单一指标的局限性,为松花江流域物源示踪和古地理重建提供了更精确的方法.
River sediments are widely regarded as essential archives for source-to-sink system analysis and paleogeographic reconstruction,yet their provenance signals can be substantially altered during downstream transport by tributary dilution and heterogeneous zircon fertility.Traditional provenance studies frequently overlook these factors,which can lead to biased interpretations.In the Songhua River basin,the mechanisms through which tributary inputs influence detrital zircon age variations in the mainstream,as well as the quantitative assessment of their sedimentary contributions,remain poorly constrained.In this study,detrital zircon U-Pb geochronology was conducted on sediments from the Songhua River mainstream and its major tributaries,including the Nenjiang,Jilin Songhua,and Lalin rivers.By integrating a dilution index,zircon yield correction,and inverse Monte Carlo modeling,this study evaluates the source-to-sink system of the Songhua River basin.The detrital zircon age spectra are defined by four principal age populations:202～110 Ma,523～205 Ma,2066～1564 Ma and 2747～2341 Ma.Both tributary dilution and differences in zircon yield exert substantial control on zircon age distributions.The effects of tributary dilution gradually diminish with increasing transport distance,whereas zircon-yield correction effectively mitigates biases arising from variations in zircon fertility among source rocks.Two recommendations for provenance studies are proposed:① sampling sites should avoid river confluence zones and preferably be located at least 50～100 km downstream from confluences;and ②zircon-yield correction should be prioritized to enhance the accuracy of provenance assessments.Zircon reproducibility tests demonstrate the absence of～1800 Ma ages in detrital zircon records from the Jilin Songhua River,suggesting that reliance solely on prominent age peaks is insufficient to fully capture regional magmatic-tectonic events.By integrating tributary dilution and zircon-yield controls and combining detrital and igneous zircon datasets,this study addresses the limitations of single-indicator provenance methods and establishes a more robust framework for sediment provenance tracing and paleogeographic reconstruction in the Songhua River basin.
刘思宁;张艳;孙磊;刘海金;王艳茹;谢远云;魏振宇;汪烨辉;祁昊东;吴鹏
哈尔滨师范大学地理科学学院,黑龙江 哈尔滨,150025自然资源部第二地理信息制图院,黑龙江 哈尔滨,150081哈尔滨师范大学地理科学学院,黑龙江 哈尔滨,150025||哈尔滨师范大学寒区地理环境监测与空间信息服务黑龙江省重点实验室,黑龙江 哈尔滨,150025哈尔滨师范大学地理科学学院,黑龙江 哈尔滨,150025哈尔滨师范大学地理科学学院,黑龙江 哈尔滨,150025||哈尔滨师范大学寒区地理环境监测与空间信息服务黑龙江省重点实验室,黑龙江 哈尔滨,150025哈尔滨师范大学地理科学学院,黑龙江 哈尔滨,150025||哈尔滨师范大学寒区地理环境监测与空间信息服务黑龙江省重点实验室,黑龙江 哈尔滨,150025哈尔滨师范大学地理科学学院,黑龙江 哈尔滨,150025哈尔滨师范大学地理科学学院,黑龙江 哈尔滨,150025哈尔滨师范大学地理科学学院,黑龙江 哈尔滨,150025湖南科技大学地球科学与空间信息工程学院,湖南 湘潭,411201
松花江流域河流沉积物锆石U-Pb年龄支流稀释锆石产率锆石可再现性
Songhua River basinriver sedimentzircon U-Pb agetributary dilutionzircon fertilityzircon reproducibility
《地质学报》 2026 (8)
2851-2869,19
本文为黑龙江省自然科学基金项目(编号ZD2023D003)、国家自然科学基金项目(编号42171006)和哈尔滨师范大学学术创新项目(编号XKB202314)联合资助的成果.
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