华北地区重力和地形及其对克拉通破坏深部过程的约束  

Constraints of Gravity and Topography on the Destruction of North China Craton

作　　者：许田 黄金水 XU Tian;HUANG Jinshui(Laboratory of Seismology and Physics of Earth’s Interior,School of Earth and Space Sciences,University of Science and Technology of China,96 Jinzhai Road,Hefei 230026,China;Mengcheng National Geophysical Observatory,96 Jinzhai Road,Hefei 230026,China)

机构地区：[1]中国科学技术大学地球和空间科学学院地震与地球内部物理实验室,合肥市230026 [2]蒙城地球物理国家野外科学观测研究站,合肥市230026

出　　处：《大地测量与地球动力学》2020年第5期517-521,共5页Journal of Geodesy and Geodynamics

基　　金：国家自然科学基金(41674096,41474082,91014005)。

摘　　要：以重力和地形数据研究现今华北克拉通区域岩石圈热化学结构,探讨华北克拉通破坏过程。首先计算自由空气重力异常、布格重力异常、Airy均衡重力异常;再利用地震学莫霍面观测从地形和布格异常中扣除对应部分,计算残余重力异常及残余地形;最后对残余重力异常进行剩余密度反演。结果表明:1)华北克拉通中、东部存在浮力;2)克拉通东部由温度效应引起的密度负扰动效应略强于化学组分差异引起的密度正扰动;3)现今华北克拉通东部是古老克拉通型地幔和新生正常地幔的混合物,约保留50%~60%古老克拉通地幔成分;4)由重力和密度约束得到的混合地幔结果支持前人提出的多期幕式拆沉的华北克拉通深部破坏过程。We analyzed the thermochemical structure of north China Craton(NCC)from gravity and topography data.After calculating the free air gravity anomaly,Bouguer gravity,isostatic gravity,residual topography,residual gravity and the corresponding inverted density,we find that:1)there is excess buoyancy in central and eastern parts of NCC;2)more buoyant newly-formed lithosphere indicate that high temperature is dominant in bivariate function of temperature and chemical composition;3)as much as 50-60 percent of old original Craton lithospheric material may still stay in the present-day ENCC lithosphere,thus supporting the episodic and multi-staged delamination numerical studies.

关 键 词：华北克拉通 岩石圈地幔 重力 地形 拆沉 

分 类 号：P312[天文地球—固体地球物理学] P313[天文地球—地球物理学]