河南新乡第四纪地层划分与沉积环境分析

发布时间：2018-05-12 18:34

本文选题：第四纪 + 地层划分　；参考：《现代地质》2017年01期

【摘要】：新乡位于豫西北山地与豫东平原过渡位置,黄河冲积扇的不断发展以及第四纪早期的新构造运动对该区第四纪沉积过程产生影响。通过对新乡多个钻孔岩心进行系统性描述、年龄测试、沉积相分析以及钻孔地层间对比分析,结果显示:黄河冲积扇的发展及黄河主河道的南北向迁移,是研究区第四纪沉积过程的重要影响因素,研究区第四纪沉积相以河流相为主,横向上对比良好;多个场地的钻孔揭示研究区全新统厚度约10 m,平均年龄9.5 ka左右;更新统上部厚度约69 m,平均年龄129 ka左右;更新统中部厚度约55 m,平均年龄小于829 ka;更新统下部未见底。在第四纪早期,黄河冲积扇主河道在研究区西侧,尚未发育到新乡地区,对该区的影响较小,以细粒的泛滥平原沉积物为主;第四纪中期,黄河冲积扇快速向东部发展,河道迁移至研究区北东侧,沉积了明显的河流相,砂体厚度明显增加;第四纪中晚期,基本继承前期的河流相沉积,随着河道南迁,砂体含量有所下降。受到新构造运动的影响,新乡地区第四纪地层北东部出现沉积间断,并且局部地区出现差异沉降,北东侧地势高于南西侧。
[Abstract]:Xinxiang is located in the transitional position between the mountainous region of the western part of Henan Province and the eastern plain of Henan Province. The continuous development of the alluvial fan of the Yellow River and the Neotectonic movement in the early Quaternary period affected the sedimentary process of the Quaternary period in this area. Through systematic description, age test, sedimentary facies analysis and correlation analysis of borehole strata in Xinxiang, the results show that the development of the alluvial fan of the Yellow River and the north-south migration of the main channel of the Yellow River, Quaternary sedimentary facies in the study area are mainly fluvial facies and well contrasted horizontally, and the boreholes in many sites reveal that the thickness of the new series is about 10 m and the average age is about 9.5 ka. The upper part of the Pleistocene is about 69 m thick with an average age of about 129 ka, while the middle part of the Pleistocene is about 55 m thick with an average age of less than 829 ka, and the lower part of the Pleistocene has no bottom. In the early Quaternary, the main channel of the alluvial fan of the Yellow River in the west of the study area has not developed to the Xinxiang area, and the influence on the area is relatively small, mainly in the fine-grained flood plain sediments, and in the middle of the Quaternary, the alluvial fan of the Yellow River developed rapidly to the east. The channel migrates to the north and east side of the study area and deposits obvious fluvial facies and the thickness of sand body increases obviously; in the middle and late Quaternary period, the fluvial facies of basic succession period is deposited, and the content of sand body decreases with the southward migration of the river course. Under the influence of neotectonic movement, sedimentary discontinuity occurred in the eastern part of Quaternary strata in Xinxiang area, and differential subsidence occurred in some areas, and the north east side was higher than the south west side.
【作者单位】：中国地质科学院地质研究所;中国地质大学(北京)地球科学与资源学院;
【基金】：河南省地震局“新乡市活断层探测与地震危险性评价”项目(HP-2011-502-5)
【分类号】：P534.63

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