摘要
利用在华北克拉通中西部横跨鄂尔多斯盆地西缘、银川地堑、黄河断裂带和贺兰山山前断裂布设的一条长度500 km的高分辨地震宽角反射/折射探测剖面资料,获得了P波震相走时,并利用多种计算方法获得该区的一维地壳速度结构模型。结果显示:银川盆地及其两侧区域的地壳速度结构和壳内界面分层都显示出较大的差异,银川盆地及以西区段呈现三层地壳结构,下地壳界面仅在鄂尔多斯块体西部显示,地壳结构呈现双层特征,且壳内速度等值线和界面变化相对平缓,显示出稳定的地壳结构特征;沿地震测深剖面地壳厚度总体呈现自东向西逐渐加厚的特征,各个块体又具有各自的地壳厚度特征。结合该区其他地球物理、地质资料等研究结果,分析了银川地堑与相邻地块的基底结构、深部构造差异,探讨其横向差异及不同地区的构造变形特征。此结果为深入认识华北克拉通中西部空间差异性、构造薄弱带或活动构造带的深、浅构造特征研究提供了精细的地球物理参数。
The travel time of P-wave seismic phase is obtained using a 500 km long high-resolution seismic wide-angle reflection/refraction detection profile across the western edge of Ordos Basin,Yinchuan graben,Yellow River fault zone and Helan Mountain piedmont fault in the central and western part of North China Craton,and the one-dimensional crustal velocity structure model in this area is obtained by several calculation methods.The results show that the crustal velocity structure and the stratification of the inner crust interface between the Yinchuan Basin and its two sides are highly different.The Yinchuan Basin and its western section present a three-layer crustal structure.The C2 interface exists in the west of the Ordos block merely.The crustal structure shows a double-layer feature,and the variation of the inner crust velocity isoline and interface is relatively gentle,exhibiting the stable crustal structure;Along the seismic sounding section,the crustal thickness generally presents the characteristics of gradually thickening from east to west,and each block has its crustal thickness characteristics.The differences in basement structure and deep structure between Yinchuan graben and adjacent blocks are analyzed with the research results of other geophysical and geological data in this area,and their transverse differences and structural deformation characteristics in different areas are discussed.The result provides fine geophysical parameters for the in-depth understanding of the spatial differences between the central and western parts of the North China Craton and the deep/shallow structural characteristics of the weak structural belt or active structural belt.
作者
孙一男
王亮
程国亮
SUN Yinan;WANG Liang;CHENG Guoliang(Geophysical Exploration Center,CEA,Zhengzhou 450002,China)
出处
《华北地震科学》
2022年第3期40-49,共10页
North China Earthquake Sciences
基金
国家自然科学基金重点支持项目(91214205)
国家自然科学基金面上项目(41474076)。
关键词
华北克拉通中西部
人工地震测深
地壳速度结构
地壳特征
central and western parts of the North China Craton
artificial seismic sounding
crustal structure
crust characteristic
