摘要
中国南方第四纪红土的物质来源一直是第四纪研究的热点。本文通过将安徽宣城剖面(XC剖面)第四纪红土的地球化学分析结果和碎屑锆石U-Pb年龄分析结果进行对比,讨论了该剖面红土的物质来源特征。XC剖面红土的地球化学分析结果显示,剖面不同深度地球化学指标的变化特征与红土的风化特征不吻合,反映了该剖面红土的物质来源存在明显随时间变化而变化的特征。而碎屑锆石U-Pb年龄的示踪结果显示,XC剖面红土的主要物质来源为附近水阳江沉积物,且随时间变化不明显。这种矛盾的结果很可能说明了碎屑锆石U-Pb年龄只能指示红土中近源的粗粒组分物质来源,而红土中富含的细粒组分仍需要借助其他示踪指标来进行综合分析。
The provenance of Quaternary Red Clay(QRC)in southern China has always been a hotspot of Quaternary research.This paper discussed the provenance characteristics of the QRC in the Xuancheng Xiangyang profile(the XC profile)of Anhui province by comparing the geochemical analysis results with the analysis results of the detrital zircon U-Pb ages.The geochemical analysis results of the trace element ratio and rare earth element ratio of the QRC in the XC profile show that the variations of geochemical indicators at different depths of the profile do not match with the weathering characteristics of the QRC,which reflects that the provenance of the QRC in this profile changes with time obviously.Comparing the analysis results of the detrital zircon U-Pb ages in the XC profile with the possible material source areas nearby,we found that although the sediments of the Yangtze River are likely to contribute to the source of the QRC in the XC profile,the amount is limited.The detrital zircon ages in the XC profile have a good correspondence with the Mesozoic Cretaceous strata exposed in the nearby Shuiyang river basin.This reflects that the Xuancheng QRC has obvious near-sourced characteristics,and its material mainly comes from the floodplain sediments of the Shuiyang River and hardly changes with time.Previous studies have shown that the QRC is mainly distributed to the south of the Yangtze River.The distribution area of QRC is far away from the typical northern dust source area.The blocking effect of hills and mountains in the south,high vegetation coverage,and other limiting factors make the heavy minerals in the northern dust carried by the winter monsoon rarely reach the areas south of the Yangtze River.In addition,due to technical limitations,it is necessary to select larger diameter particles for age analysis of detrital zircons.These large particles of heavy minerals cannot be transported long distances by wind.All these indicate that the detrital zircon U-Pb age can only trace the provenance of the coarse-grained
作者
杨立辉
程菲
陈洁
方媛
张亦赟
YANG Lihui;CHENG Fei;CHEN Jie;FANG Yuan;ZHANG Yiyun(School of Geography and Tourism,Anhui Normal University,Wuhu 241002,China)
出处
《地理研究》
CSCD
北大核心
2023年第9期2508-2519,共12页
Geographical Research
基金
安徽省自然科学基金项目(2008085MD117)
安徽省大学生创新创业训练计划项目(S202110370424)。
关键词
第四纪红土
物源示踪
地球化学
锆石U-PB年龄
Quaternary Red Clay
provenance tracing
geochemistry
detrital zircon U-Pb age
