永定河中下游廊固凹陷北部ACX02 钻孔地层年代学研究

第四纪地层年代学格架的建立对于区域地层对比及古地理环境演化研究具有重要意义。通过分析永定河中下游地区廊固凹陷北部后王各庄村ACX02钻孔378 m岩芯沉积物的结构构造、岩性组合特征，应用测井曲线及古地磁、AMS14C、OSL测年方法，对ACX02钻孔剖面进行详细地层划分、沉积相研究及地层年代学格架的建立。结果表明，岩芯记录了布容正向极性时、贾拉米洛极性亚时、奥尔都维极性亚时和高斯正极性亚时，地层从老到新依次为:下更新统（Qp1）以河道相、泛滥平原相沉积为主，底界260 m；中更新统（Qp2）以湖沼相沉积为主，底界76.7 m；上更新统（Qp3）主要为河道相沉积，底界59.7 m；全新统（Qh）主要为泛滥平原相沉积，底界15.45 m。 

STRATIGRAPHIC GEOCHRONOLOGY OF ACX02 BOREHOLE IN THE MIDDLE AND LOWER REGION OF THE YONGDING RIVER, THE NORTH OF THE LANGGU DEPRESSION

The establishment of quaternary stratigraphic chronology framework is of great significance to the study of regional stratigraphic correlation and paleogeographic environment evolution. The structural construction and lithological composition characteristics of the 378m core sediments of the ACX02 borehole in Houwanggezhuang village in the north of the Langgu depression in the middle and lower reaches of Yongding river were analyzed. Using methods of well logging, paleomagnetism, AMS¹⁴C and OSL dating, detailed stratigraphic division, study of sedimentary facies, and establishment of stratigraphic chronology framework were carried out for ACX02 borehole profile. The results show that:the core records the sub-time of positive polarity of bujong, jaramillo, ordovi and gauss; The strata from old to new are:the lower pleistocene (Qp¹) is dominated by fluvial and flood plain facies with a bottom boundary of 260 m; the middle pleistocene (Qp²) is dominated by limnetic sedimentary with a bottom boundary of 76.7 m; the upper pleistocene (Qp³) is dominated by fluvial facies with a bottom boundary of 59.7 m; the holocene (Qh) is dominated by flood plain facies with a bottom boundary of 15.45 m.