鄂西地区基底构造特征新认识——基于重磁场特征的判别  

New Perspectives on the Basement Tectonic Features in Western Hubei——Based on the Discrimination of Gravity and Magnetic Fields Characteristics

作　　者：梁学堂 李义 徐元璋 陈宇峰 Liang Xuetang;Li Yi;Xu Yuanzhang;Chen Yufeng(Geophysical Exploration Party, Hubei Bureau of Geology and Mineral Exploration, Wuhan Hubei 430056, China)

机构地区：[1]湖北省地质局地球物理勘探大队,湖北武汉430056

出　　处：《工程地球物理学报》2020年第4期432-440,共9页Chinese Journal of Engineering Geophysics

基　　金：湖北省宜昌地区重力成果集成与页岩气储层关系研究(编号:ETZ201807A03)。

摘　　要：为了研究区内基底构造特征,利用鄂西地区四幅1/25万图幅的区域重力及航磁数据,经过位场转换、分离及定量反演,揭示了鄂西地区盖层之下具有“昆阳式”、“川中式”、“江南式”三类性质的基底,呈“一盖多底”的构造特征。在基于重磁场特征对区内基底分界线进行厘定和埋深计算的基础上,对区内基底构造单元又进行了划分,在昆阳式基底区划分了2个二级构造单元、在川中式基底区划分了7个二级构造单元、在江南式基底区划分了3个二级构造单元。本次研究重构鄂西地区盖层之下基底的构造特征,在研究中元古代以来地层的构造变形、分析区内沉积环境对页岩气生藏的影响方面及解决其他重大基础地质问题等方面,具有重要的科研及现实意义。To study the basement tectonic features in the Western Hubei,this paper reveals that three types of basements with different geologic natures,that is,the‘Kunyang style’,‘Chuanzhong style’and‘Jiangnan style’are covered by a single overlying strata by potential field transformation,anomaly separation and quantitative inversion of the regional gravity and aeromagnetic data with the spatial scale of 1:250000.Based on the characteristics of the gravity and magnetic fields,the spatial boundaries and the buried depths of the basements in the study region are respectively determined and calculated.Moreover,the basement tectonic units are divided with two,seven and three second-order basement tectonic units divided respectively in the basement regions of Kunyang,Chuanzhong and Jiangnan styles.This study has reconstructed tectonic features under the caprock in the Western Hubei,and has great significance on the research of tectonic deformations of the stratum since the Middle Proterozoic,the analysis of impact of sedimentary environment on the generation and deposit of the shale gas,and the solving of some fundamental geological problems.

关 键 词：区域重力 航磁异常 结晶基底 褶皱基底 鄂西地区 

分 类 号：P631[天文地球—地质矿产勘探]