雄安新区壳幔结构揭示的大陆岩石圈改造模式  

Crust-Mantle Structure in Xiong’an New District and Its Implications for Continental Lithosphere Transformation

作　　者：张合[1] 蒋一然 王虹宇 温景充 宁杰远[3] ZHANG He;JIANG Yiran;WANG Hongyu;WEN Jingchong;NING Jieyuan(Hebei Earthquake Agency,Shijiazhuang 050021;School of Mathematics,Harbin Institute of Technology,Harbin 150001;School of Earth and Space Sciences,Peking University,Beijing 100871)

机构地区：[1]河北省地震局,石家庄050021 [2]哈尔滨工业大学数学学院,哈尔滨150001 [3]北京大学地球与空间科学学院,北京100871

出　　处：《北京大学学报（自然科学版）》2024年第6期1079-1093,共15页Acta Scientiarum Naturalium Universitatis Pekinensis

基　　金：河北省重点研发计划项目社会公共事业创新专项(22375406D);河北雄安新区管理委员会应急管理局《雄安新区深部结构探测项目(三次)》委托项目(HBCT-220510-001);国家重点研发计划雄安新区科技创新专项(2023XAGG0067);中国石油-北京大学基础研究合作项目资助。

摘　　要：利用宁杰远科研小组2022年10月到2023年7月期间布设的台间距约为16km的甚宽频带密集地震观测资料,基于蒋一然新发展的基于人工智能的远震瑞利面波频散曲线提取技术,获得大量高质量远震瑞利面波频散曲线,在此基础上进行考虑了有限频效应的相速度成像以及基于马尔可夫链蒙特卡罗非线性技术的S波速度结构反演,得到雄安新区的壳幔S波速度结构。基于S波速度结构得到以下认识:1)太行山地壳下方直接与软流圈物质相接触;2)太行山东南部华北平原地壳下方存在厚度不大的岩石圈地幔;2)太行山与其东部区域的地壳之间具有存在和不存在巨厚镁铁质下地壳的区别;太行山山前断裂一带是中生代晚期以来导致古老岩石圈拆沉的地幔热物质上升的核心区域;该地区岩石圈新生代以来经历的是拉伸兼冷却的地球动力学过程。最后,提出雄安新区高热流值的动力学模式。Based on a newly developed AI-based method for extracting teleseismic Rayleigh wave dispersion curves by Y.R.Jiang,a large volume of high-quality teleseismic Rayleigh wave dispersion curves was obtained from very broadband dense seismic observation data collected by J.Y.Ning team from October 2022 to July 2023 with station spacing of approximately 16 km.Phase velocity imaging considering finite-frequency effects and S-wave velocity inversion based on the nonlinear Markov Chain Monte Carlo technique were conducted,yielding a S-wave velocity structure of the crust and mantle in the Xiong’an New District.The S-wave velocity structure indicates that the lower crust beneath the Taihang Mountains is in direct contact with asthenosphere,while a relatively thin lithospheric mantle exists beneath the North China Plain to the southeast of Taihang Mountains.The crust in the Taihang Mountains and its southeast adjacent area shows differences in the presence or absence of a thick mafic lower crust.The fault zone at the front of the Taihang Mountains has been the core area for the ascent of mantle thermal material,leading to the foundering of the ancient lithosphere since the Late Mesozoic.Since the Cenozoic,the region has undergone a tectonic process of lithospheric extension and cooling.This study also proposes a dynamic model for the high heat flow in the Xiong’an New District.

关 键 词：大陆岩石圈 华北克拉通 雄安新区 壳幔结构 克拉通破坏 

分 类 号：P548[天文地球—构造地质学]