三门峡盆地三门组的特征与时代  

CHARACTERISTICS AND AGE OF THE SANMEN FORMATION IN SANMENXIA BASIN

作　　者：潘卿 肖国桥[2,3] 赵卿宇 杨吉龙 王强[4] PAN Qing;XIAO Guo Qiao;ZHAO Qing Yu;YANG Ji Long;WANG Qiang(Planetary Environmental and Astrobiological Research Laboratory,School of Atmospheric Sciences,Sun Yat-sen University,Zhuhai 519000;Hubei Key Laboratory of Critical Zone Evolution,School of Geography and Information Engineering,China University of Geosciences,Wuhan 430078;State Key Laboratory of Biogeology and Environmental Geology,School of Earth Sciences,China University of Geosciences,Wuhan 430078;Tianjin Centre,China Geological Survey,Tianjin 300170)

机构地区：[1]中山大学大气科学学院行星环境与宜居性研究实验室,广东珠海519000 [2]中国地质大学(武汉)地理与信息工程学院流域关键带演化湖北省重点实验室,湖北武汉430078 [3]中国地质大学(武汉)地球科学学院生物地质与环境地质国家重点实验室,湖北武汉430078 [4]中国地质调查局天津地质调查中心,天津300170

出　　处：《地层学杂志》2023年第1期91-101,共11页Journal of Stratigraphy

基　　金：国家自然科学基金(41888101、41830319、41972196)资助。

摘　　要：汾渭盆地在上新世至早更新世发育巨型内流湖泊——三门古湖。三门组是三门古湖内沉积的一套河湖相地层,同时是中国北方重要的新生代陆相地层单位。三门组沉积结束是指示黄河贯通的重要标志之一,但对三门组命名地三门峡盆地黄底沟剖面的研究显示,其岩性特征及地层时代与汾渭盆地内其他次级盆地的三门组明显不同,这不利于三门组的划分和对比,也导致了学术界对黄河贯通三门峡时代的争议。最近,我们对三门峡盆地东部平陆县张村镇后沟村出露的三门组做了详细的沉积特征和磁性地层研究,结果表明:(1)三门峡盆地三门组的地层特征和时代(2.7—1.6 Ma)与汾渭盆地内其他次级盆地基本一致,指示黄河袭夺三门古湖的时间大约为1.6 Ma,与其他证据揭示的黄河贯通三门峡的时间一致;(2)之前作为三门组命名剖面的黄底沟剖面可能因黄河的侵蚀而缺失了三门组,修订后的磁性地层年代框架指示该剖面可能保存了上新统游河组和上中新统灞河组。三门组在三门峡盆地多个剖面均有出露,本文建议将地层连续、界线清晰、出露最佳、有详细古地磁定年且交通便利的后沟剖面作为三门组的标准剖面。The Sanmen paleolake,a Plio-Pleistocene endorheic mega-lake situated in the Fenwei Basin,contains a series of fluvio-lacustrine sediments called the Sanmen Formation,which is an important Cenozoic terrestrial lithostratigraphic unit in the Northern China.The termination of the Sanmen Formation is one of the most important indicators for the integration of the Yellow River.The Huangdigou Section within the Sanmenxia Subbasin is the type section of the Sanmen Formation,however,previous studies shown that the stratigraphic lithology and chronology of the Sanmen Formation in the Huangdigou Section are inconsistent with the other subbasins among the Fenwei Basin.This discrepancy hinders stratigraphical division and correlation for the Sanmen Formation,and has also caused the divergence on the exact age of the integration of the Yellow River.Recently,we reported detailed magnetostratigraphic and sedimentary study for the Sanmen Formation in the Hougou Section,Zhangcun Town,Pinglu County,which is located in the eastern Sanmenxia Subbasin.Our results show that the stratigraphic characteristics and chronology(2.7–1.6 Ma)of the Sanmen Formation are consistent with the other subbasins among the Fenwei Basin,indicating that the Sanmen paleolake was captured by the Yellow River at~1.6 Ma which is further supported by other lines of evidence.In addition,the revised magnetostratigraphic chronology demonstrated that the Huangdigou Section,the type section of the Sanmen Formation,may lacks the Sanmen Formation due to the erosion of the Yellow River.Actually,this section probably only preserved the Pliocene Youhe Formation and the Upper Miocene Bahe Formation.Here we recommend the well-exposed Hougou Section as the type section for the Sanmen Formation,because of its complete and successive stratigraphy,clear boundaries,reliable magnetostratigraphic dating,and convenient transportation.

关 键 词：三门组 三门古湖 下更新统 第四纪 汾渭盆地 

分 类 号：P534.63[天文地球—第四纪地质学]