北京西山木城涧地区中侏罗世窑坡组砂岩粒度特征及沉积环境研究  

Study on grain-size characteristics and sedimentary environment of sandstone of Middle Jurassic Yaopo Formation in Muchengjian area of Xishan,Beijing

作　　者：王浪浪 魏涛 曾昭霞 冉文瑞 陈茜 刘芸 WANG Langlang;WEI Tao;ZENG Zhaoxia;RAN Wenrui;CHEN Qian;LIU Yun(Guizhou Institute of Natural Resources Planning and Survey,Guiyang 550004,China)

机构地区：[1]贵州省自然资源勘测规划研究院,贵阳550004

出　　处：《华北地质》2025年第1期44-57,共14页North China Geology

基　　金：贵州省资源厅项目“贵州省铝土矿资源勘查开发利用与保护专项规划(2024—2030年)”。

摘　　要：【研究目的】北京西山木城涧地区中侏罗世窑坡组发育典型的陆相湖泊沉积。该套地层是中侏罗世砂岩发育最好、出露较全沉积地层,但其粒度特征却缺少研究,制约了华北地区中侏罗世沉积环境的分析和重建。【研究方法】本文基于北京西山木城涧地区潘涧沟野外露头剖面,通过镜下观察、统计和分析,计算其相关粒度参数、萨胡函数判别值等,并绘制概率粒度曲线图、弗里德曼粒度参数散点图以及C-M图,综合研究总结出窑坡组砂岩粒度特征及沉积环境。【研究结果】研究区目标剖面的18个砂岩样品的相关粒度参数如下:①平均粒径范围0.57~3.54φ;②标准偏差σ值范围0.42~1.03;③偏度(SK_(1))范围﹣2.36~0.79;④峰度(KG)范围0.90~1.27;概率累积曲线为典型的二段、三段及多段式;样品C-M图显示沉积物以悬浮搬运、递变悬浮为主,均代表了典型的牵引流沉积。【结论】SK_(1)-σ_(1)散点图、概率累积曲线、C-M图等显示研究区沉积环境为滨浅湖及三角洲沉积。[Objective]The Middle Jurassic Yaopo Formation in the Muchengjian area of Xishan,Beijing,belongs to typical continental lacustrine deposits.This set of strata is the best developed and fully exposed sedimentary of Middle Jurassic sandstone,but its grainsize characteristics are not researched,which restricts the analysis and reconstruction of the Middle Jurassic sedimentary environment in North China.[Methods]Based on the outcrop profile of Panjiagou in Muchengjian area,Western Beijing,this paper calculates the relevant particle size parameters and Sahu function discriminant values through microscope observation,statistics and analysis,and the probability particle size curve,Friedmann particle size parameter scatter plot and C-M diagram were drawn,and the relevant parameters and images were comprehensively studied and analyzed,and the grain size characteristics and sedimentary environment of the sandstone of the Yaopo Formation were summarized.[Results]Relevant grain-size parameters of 18 sandstone samples from the target profile of the study area were as follows:(1)the average particle size ranges from 0.57-3.54φ;(2)Standard deviationσranges from 0.42 to 1.03;(3)Skewness(SK_(1))range-2.36-0.79;(4)kurtosis(KG)ranges from 0.90 to 1.27;the probability granularity accumulation curves are typical two-stage,three-stage and multi-stage forms.The C-M diagram of the sample shows that the sediments are mainly suspended and gradually suspended,which represent typical traction flow deposits.[Concluslions]SK_(1)-σ_(1) scatter plots,probability accumulation curves,C-M plots,show that the sedimentary environment in the study area is shallow lake and delta sedimentation.

关 键 词：薄片粒度图像分析法 沉积环境 窑坡组 北京西山 

分 类 号：P585[天文地球—岩石学]