本文基于最新的全球重力场模型TopexV18.1数据,在区域背景尺度下,计算了华北地区的区域布格重力异常,并反演了Moho面分布特征;在此基础上结合区域地热流测量数据,讨论重力均衡和热均衡调整过程对现今地形的影响;最后,结合已有的速度结构模型和岩石圈热参数,对10个次级块体单元的热均衡特点开展了综合对比研究.研究结果表明:华北地区构造块体单元之间由于克拉通底部受到不同程度的破坏,不仅深部构造特征差异性明显,而且其构造热均衡特点也不尽相同.根据平均地震波速去掉重力均衡作用后恢复的高程热流关系表明,均衡作用对于现今地形的改造作用十分显著,但根据该方法对燕山隆起和冀中坳陷两个块体的恢复效果不明显.
In this paper, based on the up to date global free-air gravity anomaly dataset (TopexV18.1), we computed the Bouguer gravity anomaly of north China area and studied its Moho structure. Moreover, using the regional heat flow dataset, we discussed the gravity and thermal effect in the isostasy mechanism on the present topography. Finally, combined with existing velocity model and thermal parameters of lithosphere, we carried out thermal isostasy contrast studies for 10 secondary block units. The results are important for understanding the deep structure and regional isostasy pattern in north China. The results show that there are distinct differences both in the deep structures and thermal isostasy characteristics because of the various destruction of the bottom of north China craton. The recovery relationship of topography and heat flow after deducting the gravity effect from the average seismic wave velocity indicates that there is very remarkable effect for the present topography. But the effect is not obvious in the Yanshan uplifted zone and Jizhong depressions block.