鲁西隆起地壳厚度和泊松比及其地质意义

The crustal thickness and Poisson's ratio beneath the Luxi uplift area and its geological significance

鲁西隆起是华北克拉通东部重要的伸展构造,为分析鲁西隆起地区地壳结构特征,本文通过选取2010-2013年鲁西隆起及周边地区28个地震台站记录的102个远震波形（MS〉6.0、震中距30°~90°）,利用远震接受函数方法获得各台站下方的地壳厚度、泊松比值,结果显示：鲁西隆起地区地壳厚度值大致在29.9~36.1km之间,地壳厚度最小的区域位于北部地区,总体表现为南北向的变化特征,向南逐渐增大;相反,鲁西隆起北部地区的地壳平均泊松比值最大,向南逐渐减小.根据地壳厚度、泊松比分布特征,本文认为鲁西隆起地区的地壳结构特征是由地幔的主动上涌及对地壳的热侵蚀作用造成,这在北部地区表现最为典型.鲁西隆起伸展构造的形成是华北岩石圈减薄过程中地壳响应的结果,表明中生代华北岩石圈减薄过程存在明显的热侵蚀作用.

Luxi uplift is the important extensional tectonics in the North China Craton.In order to analyse the characteristics of crustal structure beneath the Luxi uplift,We collected 102 seismic waveforms（MS〉6.0,epicenter distance between 30°~90°）which recorded by 28 seismic stations in the Luxi uplift and its surrounding areas from 2010 to 2013,and we obtained the crustal thickness and Poisson＇s ratio beneath each station from Tele-seismic receiver function study.The results showed that：the crustal thickness of Luxi uplift area is between 29.9~36.1km,the crustal thickness is the thinnest in the north,mainly changes in the north-south direction and increases toward-south;In contrast,Luxi uplift average Poisson＇s ratio of crustal in northern area of Luxi uplift is largest,and gradually decreasing to south.According to the chatacteristics of the crustal structure and Poisson＇s ratio beneath Luxi uplift area,We concluded that the characteristics of crustal structure of Luxi uplift area are caused by the mantle upwelling actively and the earth＇s crust is been thermal erosion,especially the northern area of the Luxi uplift.The formation of Luxi uplift is the response of the lithospheric thinning of the North China in crust,and showed the lithospheric thinning process of the North China exists significant thermal erosion in Mesozoic.