永定河冲洪积平原南部QHJ01孔第四纪地层划分及其环境意义  

Quaternary stratigraphic division and its environmental significance of Borehole QHJ01 in southern alluvial plain of the Yongding River

作　　者：程天赦[1] 杨文静[1] 代鹏 张杰[2] 邓晓红[2] 冯杰[2] 武军杰[2] 刘东明[2] CHENG Tian-she;YANG Wen-jing;DAI Peng;ZHANG Jie;DENG Xiao-hong;FENG Jie;WU Jun-jie;LIU Dong-ming(Institute of Tianjin Geological Survey,Tianjin 300191,China;Institute of geophysical and geochemical exploration,China Academy of Geological Sciences,Hebei 065000,China)

机构地区：[1]天津市地质调查研究院,天津300191 [2]中国地质科学院地球物理地球化学勘查研究所,河北065000

出　　处：《华北地质》2021年第4期47-54,共8页North China Geology

基　　金：中国地质调查局项目“永定河冲积平原区域地质调查(DD20160046)”。

摘　　要：对永定河冲积平原南部固安县东三更生村501 m深的QHJ01孔岩心进行了岩石地层、磁性地层、AMS14C和光释光(OSL)测年等研究。结果表明:(1)Matuyama(松山)/Gauss(高斯)和Brunhes(布容)/Matuyama(松山)极性界线分别位于231.2 m和78.7 m处,结合岩石地层学及生物地层学特征,确定地层埋深在231.2 m、78.7 m处分别作为下更新统、中更新统的底界。(2)通过AMS14C、光释光(OSL)测年,确定上更新统和全新统的底界深度分别位于53.5 m和25.5 m。(3)古永定河冲洪积扇在上新世末期即到达了固安地区,其岩石地层学标志是上新世首次出现的厚层"泥包砾"层之上含大量泥砾的砂层。(4)第四纪以来,永定河冲洪积平原南部(固安地区)为永定河多期改道与摆动形成的泛滥沉积环境。本研究为廊(坊)固(安)凹陷中心地带第四纪地层划分对比、古地理环境演化研究,提供了重要的年代地层格架。Based on the core materials collected from the Borehole QHJ01,which is located at Dongsangengsheng village of Guan county in southern alluvial plain of the Yongding River and has a depth of 501 m,the analyses of lithostrotigraphy,magnetostratigraphy,AMS14 C and OSL dating,ostracoda and sporopollen assemblages were carried out.The results show that:(1) The boundaries of Matuyama/Gauss polarity chron and Brunhes/Matuyama polarity chron appear at the depth of 231.2 m and 78.7 m,respectively.Combined with the characteristics of rock stratigraphy and biostratigraphy,it suggests that the bottom of the Lower Pleistocene and Middle Pleistocene is231.2 m and 78.7 m.(2) The dating of AMS14 C and OSL shows the bottom of the Upper Pleistocene and the Holocene is 53.5 m and 25.5 m.(3)The alluvial fan of the palaeo-Yongding River reached the Guan area at the end of the Pliocene,and its petrological sign is a thick gravel sand layer above the thick muddy boulder layer of the Pliocene,which was first appeared in the Pliocen.(4)Since the Quaternary,the southern part of the Yongding River alluvial plain is dominated by the overflowing sedimentary environment of the Yongding River.The present paper provided important age control for Quaternary stratigraphic division,correlation and paleogeographic environmental evolution in the central area of the Lang(fang)-Gu(an)Depression.

关 键 词：磁性地层 第四系 古永定河 廊固凹陷 永定河冲洪积扇 

分 类 号：P534.63[天文地球—第四纪地质学]